;b 117 

D984 
:opy 1 



THE 



Vitality and Germination of Seeds. 



A THESIS PRESENTED FOR THE DEGREE OF 

DOCTOR OF SCIENCE AT THE UNIVERSITY 

OF MICHIGAN IN JUNE. 1902. 



BY 

J. W. T. DUVEL. 

Holder of the Dexter M. Ferry 

Fellowship in Botany. 



/ 



THE 



Vitality and Germination of Seeds. 



A THESIS PRESENTED FOR THE DEGREE OF 

DOCTOR OF SCIENCE AT THE UNIVERSITY 

OF MICHIGAN IN JUNE, 1902. 



BY 

J. W. T. DUVEL, 

Holder of the Dexter M. Ferry 

Fellowship in Botany. 



^^Y""" 



Gift 
The University 



^ 

^ 



CONTENTS. 



Introduction 9 

Materials and methods 10 

Seeds 10 

Germination tests and ai)panitns 11 

Effect of climatic conditions on the vitality of seeds 13 

Causes of the losses in vitality in different climates 22 

Effect of moisture and temperature u])on vitality - 24 

Seeds packed in ice 26 

Effect of moisture on vitality at higher temperatures 29 

Summary 35 

Effect of definite quantities of moisture on the vitality of seeds when they are 

kept within certain known limits of temperature 36 

A comparison of methods of storing and shipping seeds in order to protect 
them from moisture, and consequently to insure a better preservation of 

vitality 44 

Suggestions of earlier investigators 44 

The necessity for thoroughly curing and drying seeds 45 

Character of the seed warehouse or storage room 46 

The value of good seed to the market gardener 46 

Shipping seeds in charcoal, moss, eti 47 

Nature of the experiments 47 

Disposition of the samples 48 

Results of the germination tests 50 

Experiments in keeping and shipping seeds in special packages 65 

Respiration of seeds 74 

Summary 81 

Enzymes in seeds and the jiart thej^ play in the preservation of vitality 82 

Sununary 87 

Literature cited 90 

7 



I L L U S T R A T I N S 



TEXT FIGURES. 



Page. 
Fig. 1. Apparatus used to determine the effect of moisture and temperature on 

the vitality of seeds in communication with free air ?>0 

2. Ai>paratus used to determine tlie effect of moisture and teniperatui-e 

on the vitaUty of seeds not in connnuni(!ation with free air oO 

8 



THE VITALITY AND GERMINATION OF SEEDS. 



INTRODUCTION. 

It has long- been known that the conditions under which plants are 
grown and the degree of maturity at the time of liarAcsting are fac- 
tors which pla}^ an important part in the life of seeds. But, granting 
that seeds are of strong vitality at the time of harvesting, there 
remain to be considered the methods of gathering and curing, the 
water content of the seed at the time of storing, the methods of stor- 
age, the humidit}' and temperature of the surrounding atmosphere, 
the composition of the seed, the nature of the seed coats, activities 
within the cells, and numerous other factors which play important 
parts in the life of the seed. 

The conditions necessary for the successful germination of a seed of 
good vitalit}" and the chemical transformations accompanying these 
earl}' stages of development have received considerable attention from 
numerous investigators. These changes and conditions are fairly well 
understood for many of our conmion seeds. However, several impor- 
tant facts still remain unexplained, and our knowledge will not be 
complete until each and every species has been carefully studied. 

On the other hand, the conditions influencing the vitalit}^ of seeds as 
commercial!}' handled are but little understood and have been almost 
wholly neglected in research work. Likewise, but little attention has 
been given to the complex chemical and physical changes which take 
place in mature seed during the slow process of devitalization. It was 
in order to determine some of these factors that the work described in 
these pages was begun, and the results are thus of considerable practi- 
cal value as well as of scientific importance. The present paper treats 
chiefly of the conditions influencing the vitality and germination of 
seeds when subjected to such methods of treatment as are generally 
met with in the ordinary handling of seed. Particular attention has 
been given to the efl'ect of climate, moisture, and temperature on 
vitality, supplemented with a discussion of the changes taking place 
in mature seeds, especially the respiratory activities and the part 
played by enzymes. 

9 



10 THE VITALITY AND GERMINATION OF SEEDS. 

Tli(^ rt'sults of the iil)ovc (!xperinicnt,s luive .su*4"gcsted improved 
luethod.s of .storing- and shipping- seed.s so as to prolong their vitality 
and also to secure the ^^I'oduction of more vigorous seedlings. 

The work for the present paper was begun in 1899 at the University 
of Michigan and was continued for three consecutive years while the 
writer held the Dexter M. Ferry Botanical Fellowship in that institu- 
tion. During this time the investigation was under the direction of 
Prof. Y. M. Spalding, Ph.D., and Dr. F. C. Newcoml)e, who showed 
great interest in it and gave valuable suggestions as the work pro- 
gressed, at the same time placing the facilities of the laboratory and 
of the library at the disposal of the writei-. Since September 1, 1902, 
the work has been continued in the Seed Laboratory of the U. S. 
Department of Agriculture. Valua])le assistance in storing seeds was 
rendered l)y Prof. C. W. Burkett, at Durham, N. H. ; Mr. E. E. Smith, 
Wagoner, Ind. T. ; Prof. W. R. Dodson, Baton Rouge, La. ; Prof. F. S. 
Earle, Auburn, Ala.; Zinuuer Brothers, Mobile, Ala.; Prof. H. H. 
HuDie, Lake City, Fla., and Prof. Charles B. Scott, San Juan, Porto 
Rico. 

MATERIALS AND METHODS. 

SEEDS. 

For these experiments thirteen different samples of seeds were used, 
being so selected as to include representatives of ten different families 
and twelve genera and species, as follows: 

Poacese — Zea mays, sweet corn (two samples). 

Liliacese, — Allium, eepa L., onion. 

Ijrassicacesd — jBras.s-lca oleracea. L., cabbage; Rn}>h(nuis mthnm L., 
radish. 

Apiacesd — Daticus carota L., carrot. 

Fabacese — Pisum sativum. L., pea; Pha.seola,s' vidga7'is L., bean. 

Yiolacese, — Viola tricolor L., pansy. 

PolemoniacedR — Phlox drmnmondii Hook, phlox. 

Solanacede — Lycopersicon lycopersicum (L.) Karst., tomato. 

Cn^curbitaceae, — Citridhis citridhis (L.) Karst., watermelon. 

Asteraeepe — Lactuca sativa L. , lettuce. 

It will thus be seen that the seeds used cover a wide range as to 
family characteristics, as well as size, structure, and composition of 
seed. Likewise they are all from plants of the garden or iield that 
have undergone a high degree of cultivation, thus enabling the seeds 
to withstand more or less variation as to conditions of vitality and 
growth. 

All seeds used throughout these experiments were provided by 
D. M. Ferry & Co., of Detroit, Mich., and the seed furnished was of 
strong vitalit}^ and of known age and origin. The corn "A" (Minne- 
sota Sweet), onion (Yellow Danvers), pea (D, M. Ferry Extra Early), 
bean (Yellow Kidney, Six Weeks), tomato (Dwarf Champion), and the 



MATERIALS AND METHODS. 



11 



watermelon (Sweet Mountain) were grown in Michigan. The corn 
"B" (Minnesota Sweet), was grown in Nebraska, the cabbage (Win- 
ningstcdt), in Washington, and the lettuce (Black-Seeded Simpson), in 
California, while the radish (Early Scarlet Turnip-Rooted), carrot 
(Chantenay), pansy (mixed), and Phlox drut/miondii (mixed) were 
grown in France. The seed was all of the harvest of 1899 and was 
received at the botanical laboratory' of the University of Michigan on 
January 27, 1900. 

On January 30, 1900, germination tests were made, showing the 
vitality of the seeds to be as follows: 





Vitality of seeds tested January SO, 1900. 




Kind of seed. 


Percent- 
age of 

germina- 
tion. 


Kind of seed. 


Percent- 
age of 
germina- 
tion. 




100 
93 

83.5 
94 

88 . 
87.5 
98 


Pansy 


69.5 




Pea 


97 




Phlox 


78 




Radish 


81 




Tomato 


98 




Watermelon 


99 


Onion 











GERMINATION TESTS AND APPARATUS. 

In the preliminary work several methods of testing were tried, but 
as none proved as serviceable as the "Geneva tester," this apparatus 
was adopted for all subsequent tests as recorded in the following 
pages. The detailed construction of this tester need not be described, 
for it is simple and quite familiar to all. However, some modifications 
were made in the preparation of the apparatus, and some precautions 
taken in the manipulation, which have proved to be of much value. 
The brass wires originally and ordinaril}^ used to support the folds of 
cloth were replaced by glass rods of 6 to T mm. diameter. Rods of 
this size are much heavier than is necessary to support the folds of 
cloth, but the chief advantage in having rods of large diameter is that 
in case of the germination of large seeds the folds can be drawn near 
together at the top and still have sufficient space within the fold for the 
seeds. On the other hand, in the germination of small seeds that 
require considerable quantities of air, the folds can be closed at the 
top bj'^ bringing the rods together, thus insuring more uniform condi- 
tions throughout the fold and at the same time leaving sufficient space 
above the seeds for an abundant supply of air. The chief advantage 
in substituting glass rods for brass wires is in removing the possible 
source of injury resulting from the poisonous action of the dissolved 
copper. 

Another error frequently, if not alwaj^s, made in using such a tester 
is in allowing the ends of the cloths, or sometimes the bottoms of the 



12 THE VITALITY AND GERMINATION OF SEEDS. 

folds, to dip into water in the pan. This should never be permitted, 
for in that way seeds are kept too moist, especiall}^ near the ends of 
the folds. Likewise such methods give an opportunity for the trans- 
mission of dissolved copper and a resultino- injury to the seeds. For 
this same reason the strips of cloth should be made sufficiently narrow 
not to come into contact with the sides of the pan. 

Much better results are o])tained if the seeds, before being placed 
in the germinator, are soaked in water for several hours, the length 
of time depending on the power of absorption of the seeds. In these 
experiments the seeds were always soaked in distilled water for twelve 
or tifteen hours before transferring them to the germinator. This 
preliminary soaking gives a more speedy germination, which is always 
advantageous, especially in making comparative germination tests. 
In order to supply the requisite amount of moisture for subse(|uent 
growth, the cloths were iirst uniformly and completel}" wet with dis- 
tilled water; moreover much care was taken to see that there was only 
a very small quantity of water in the l)ottom of the pan. In case of 
seeds that germinate readily, such as cabbage, lettuce, and onion, it is 
necessary that all surface water be removed from the bottom of the 
germinator if good results are desired. The pan then being covered 
with a glass plate. It is seldom necessary to increase the amount of 
moisture, for seeds when once soaked need only to be kept slightly 
moist and not wet, as must necessarily^ be true if the ends of the cloths 
or ))ottoms of the folds dip into the water. After soaking, the water 
in the seeds and cloths is ample for the completion of most germina- 
tion tests. However, in an occasional test the seeds may become 
slightly dry, which happens when the cover is kept off the pan for a 
considerable time while counting geriuinated seeds. In such cases the 
remedy is to pour a small quantity of water in the bottom of the pan, 
or in extreme cases to moisten the folds with a fine spray. 

If the above modifications be adopted and the necessary precautions 
taken, mau}^ of the olijections frequently made to the Geneva tester 
will be removed and the difficulties will be overcome; at least it is a 
most excellent method of testing seeds where comparative results are 
especially desired. It must also be borne in mind that the Canton flan- 
nel (which is generally used in making the pockets) should always be 
of the best grade and should never be used a second time without l)eing 
thoroughly cleaned and sterilized. 

In selecting samples for germination the impurities and the imma- 
ture seeds were first removed. The samples for test were then made 
up of the remaining large and small seed. For the most part 200 
seeds were taken for a test, but with the larger seeds — corn, pea, bean, 
and watermelon — 100 seeds were usually used. In all cases where any 
irregularity was apparent, tests were repeated. The controls are 
based on the results of several duplicate tests. 



EFFECT OP CLIMATIC CONDITIONS. 13 

All germination tests were made in a dark room where the temper- 
ature could be comparatively well regulated and was maintained nearly 
constant throughout most tests. Germinated seeds were removed daily 
during early stages of the tests and a complete record of the number 
germinating each day was kept. This is of value in seed testing, 
because the germinative energy of a seed tells much as to its vitality. 
If seeds have a high vitality, the germinative energy will be very 
strong, i. e. , germination will take place rapidly, giving rise to strong 
and vigorous seedlings; but if the seeds are of very low vitality, there 
will be a corresponding retardation in germination, giving rise to 
weak seedlings, i. e., showing a low germinative energy. In most 
cases throughout this work only the final percentages of germination 
are tabulated. 

EFFECT OF ClilMATIC CONDITIONS ON THE VITALITY OF SEEDS. 

It has long since been known that seeds under ordinarj^ conditions 
lose their power of germination after the lapse of a few years, or in 
some cases within a few weeks or months. Many investigators have 
also learned that the rapidity with which seeds lose their vitality, when 
stored under ordinary conditions, varies greatly with the section of 
the country in which such seeds are kept. This loss in vitality is espe- 
ciall}" marked in the case of seeds stored in places of relatively high 
humidity. The rapid deterioration of seeds in localities having a 
humid atmosphere has become a source of much embarrassment to 
seedsmen, for they have experienced many difficulties in shipping seed 
to such places. This is especially marked in the case of seeds sent to 
growers or dealers in the vicinity of the Gulf of Mexico. Gardeners 
and planters in that part of the United States are continually com- 
plaining about the nonviable seeds sent out by seedsmen. Some grow- 
ers have learned how to guard against this difficulty to a certain extent. 
Zimmer Brothers, of Mobile, Ala. , wrote, on February 28, 1900, con- 
cerning this matter, as follows: 

During thirty years' experience in market gardening, we have learned that seeds 
of many hardy plants will not keep in our climate, and when ordering we so time 
our order that we can plant the seeds as soon as received. If such be impossible, we 
are very careful to keep the original package unoiiened until conditions are favorable 
for planting. If we find it necessary to keep seeds of hardy plants for some months, 
we put them up on arrival in dry bottles, put on top a bit of cotton saturated with 
chloroform and cork tightly. We have kept, in that way, cauliflower seed satisfac- 
torily for twelve months. At the shore seeds keep very badly; one-half mile back 
they do much better. As a rule seeds of tender plants give but little trouble. 

As far as has been ascertained, no definite experiments have been 
made with these points in view, and especially with the idea of deter- 
mining the cause or causes of this deterioration of vital energy. In 
order to obtain reliable data on these points, a series of experiments 
was undertaken in February, 1900, to determine how seeds are affected 



14 THE VITALITY AND GERMINATION OF SEEDS. 

when (listril)uted to diti'crciit parts of the United States andsnl)niitted 
to the free influence of various climates. Likewise at tlie various 
points where tests were made the seeds were subjected to diflerent 
treatments. 

The pUices selected for these tests were San Juan, P. R., Lake City, 
Fla. , Mobile, Ala. , Auburn, Ala. , Baton Rouge, La. , Wagoner, Ind. T. , 
Durham, N. H., and Ann ArVjor, Mich. 

A sample of each species of seed was put up separately in double 
manila coin envelopes and in closely corked bottles. Duplicate sets 
of each series were then subjected at each of the above-named places 
to the following conditions: 

Trade conditions. — Conditions similar to those in which seeds are 
kept when offered for sale by retail dealers, the seed being more or 
less exposed to meteorological changes and subjected to natural varia- 
tions in temperature and humidity. For the most part the seeds were 
in rooms that were never heated. 

Dry rooms. — Rooms in the interior of buildings which were artifi- 
cially heated during cold weather, and where the (piantity of moisture 
was relatively small and the temperature comparativel}^ constant. 

Basements. — Rooms where the temperature was comparatively low 
and uniform, and the relative humidity of the surrounding air was 
much higher than in "trade conditions" and "dry rooms." 

These conditions varied in the different places at which tests were 
made, and a more detailed description will be given when the residts 
of the germination tests are discussed. 

For the first part of this paper, treating of the influence of climate 
on vitality, none of the seeds need to be considered save those pre- 
pared in paper packages and kept under trade conditions, these coming 
more nearly under the direct action of the surrounding atmosphere. 
A sample of each kind of seed was put up in a manila (No. 2) coin 
envelope, and each of these packages was then inserted in a second 
(No. 3) coin envelope. Duplicate samples of every kind of seed were 
sent to the various testing places, where they were subjected to trade 
conditions. At San Juan the packages of seeds were kept in an open 
room, being subjected to the full action of the atmosphere but pro- 
tected from the direct rays of the sun and from rain. At Lake City 
the packages were kept in a one-story frame Ijuilding which was not 
artificially heated and the doors of which were open the greater 
portion of the time. At Mobile the packages of seeds were stored in 
a comparativel}' open attic of a private dwelling. At Auburn the 
seeds were stored in a greenhouse office, with the doors frequently 
standing open. At Baton Rouge the packages were kept on a shelf in 
a grocery store, the doors of which were closed onh' during the night. 
At Wagoner the conditions were very similar to those of Baton Rouge, 
save that the packages of seeds were kept in a drug store. At Dur- 
ham the seeds were kept over a door at the entrance of one of the 



EFFECT OF CLIMATIC CONDITIONS. 



15 



college buildings. Tliis door opens into a hall wliieli coiinnuniciites 
Avith the offices, chemical l;i])oratorv, and the basement. At Ann 
Arbor the seeds Avere stored in the botanical laboratoiy, with slightlj 
vaiying conditions, they being near a window which was frequently 
open during the sunnuer, and at irregular intervals during the earl}^ 
part of the summer the packages were placed in the window so as to 
receive the direct rays of the sun. The seeds stored at Ann Arbor 
served partially as controls for those sent to the various other places, 
and, in addition to the last-named series, seeds from the original 
packages, as received from D. M. Ferry & Co., were kept in a dry 
and comparatively cool closet on the fourth floor of the botanical lab- 
oratory. These seeds served as checks for the complete set of exper- 
iments, and are designated throughout this paper as "Control." 

The samples were sent out to the above-named places in February, 
1*J00. The first complete set was returned in June, or early July, of 
that year. The second complete set was allowed to remain throughout 
the entire summer, and was returned in Octoljer and earl}^ November 
of the same year. The average time of treatment for the two series 
of experiments was 12S and 251 days respectively. When the seeds 
were returned, germination tests were made as soon as possible. The 
length of time that the seeds were in the various places and the vitality 
as shown by the germination tests are given in Tables I and II. In 
both tables the columns from left to right, beginning with Mobile, 
Ala., arc in the order of the degree to which the seeds were injured. 

Table 1.— Effect of climate on vitality, as shown by j)ercentage of germination — -fjr!<t test. 



Kind of .seed. 


Con- 
trol. 


Mobile, 

Ala., 

Feb. 17 

to 
July 7. 

140 
days. 


San 
Juan, 
P. R., 
Feb. 9 

to 

June 20. 

129 

davs. 


Baton 
Rouge, 

La., 
Feb. 17 

to 

JunelS. 

121 

days. 


Wagon- 
er, 

Ind.T., 

Feb. 17 
to 

June23. 

126 

days. 


Lake 
City, 
Fla., 
Feb. 9 

to 

June 18. 

129 

days. 


Dur- 
ham, 
N.H., 

Feb. 17 

to 

July 14. 

147 

days. 


Au- 
burn, 
Ala., 
Feb. 17 

to 
May 30. 

102 
days. 


Ann 
Arbor, 
Mich. 




96.9 
89.3 
95.8 
92.7 
S3. 6 
83.3 
95.3 
98.7 
63.0 
69.0 
95.5 
98.3 
81.6 


80.0 

48.0 

7.0 

64.5 

58.5 

59.0 

69.2 

58.0 

3.0 

0.5 

90.0 

98.0 

63.0 


96.0 
72.0 
84.5 
82.0 
64.0 
7L5 
94.0 
100.0 
20.0 
23.5 
94.0 
96.0 
79.0 


96.0 

80.0 
90.0 
88.5 
77.5 
74.3 
94.0 
96.0 
28. 5 
47.5 
91.5 
100.0 
82.5 


96.0 
70.0 
93.5 

83.5 
77.5 
81. 5 
98.0 
96.0 
48.5 
50.5 
96.5 
98.0 
78.0 


94.0 
86.0 
95.0 
89.5 
79.0 
76.5 
96. 
98.0 
44.5 
41.5 
94.0 
98.0 
87.0 


100.0 
89.3 
96. 5 
93.0 
80.6 
78.0 
98.0 

100.0 
55.5 
67.0 
94. 5 
98.0 
82.0 


96.0 
88.0 
96.0 
91.0 
75.5 
84.5 
93.3 
98.0 
.57.5 
61.5 
95.0 
94. (f 
86.5 


100.0 




92.0 




95.0 




96. 


Radish 


82.5 


Carrot 


76.0 


Pea 


90.0 


Bean 


98.0 


Pansy 


53.5 


Phlo.x; drunimondii 

Tomato 


67.0 
89.0 


Watermelon 


100.0 


Lettuce 


82.0 






Average of all seeds . 


87.79 


53.59 


75. 12 


80.48 


82.12 


83.00 


85.57 


85.70 


86.23 



From Table I it will l)o seen that the loss of vitality in the case of 
seeds stored at Mobile was much greater than in those stored at any 
of the other places. The greatest loss in the samples tested was in the 



IC) 



THE VITALITY AND GEKMINATION OF SEEDS. 



phlox, where the germination was only 0.5 per cent, or a loss in vitality 
of 09.3 per cent as compared with the control. These results were 
closely followed by a loss in vitality of 95.9 and 92.7 per cent for the 
pans}^ and onion seed, respectively. The percentages of germination 
in the other cases, except the "B" sweet corn, pea, and bean, were 
sufhcient to have produced a fair stand, i. e. , if we consider that far 
too many seeds are usually sown. But a decrease in the percentage 
of germination means seeds of a low germinative energy. Even 
though the final percentage of germination be up to standard, the 
retardation may be of vital importance. A very good example of the 
retardation in germination is shown in the tests of the watermelon 
seeds. In the control sample 94 per cent of the seed germinated in 
47^ hours, while the seed returned from Mobile showed, during the 
same time, a germination of only 12 per cent; yet the difference in the 
final germination was onl\' 0.3 per cent in favor of the control. Like- 
wise the seed returned from San Juan germinated only 20 per cent in 
47i hours, the final germination being 90 per cent or only 2.3 per cent 
lower than the control. 

Many similar cases might l)c mentioned in which the final per- 
centages of germination, as shown by the first set of tests given in 
Table I, represent a loss such as might l)e justW considered well within 
the limits of normal variation. However, that all of the samples of 
seed w^ere injured as a result of the unfavorable climatic conditions is 
shown in the second set of tests set forth in Tal)le II. In the latter 
case the seeds remained in the various places nearly twice as long as 
those used for the first test. 

Table II. — Effa't of climate on vikdity as shown h)j percentage of germination — second test. 



Kind of sued. 



Corn, sweet, "A" 

Corn, sweet, "B" 

Onion 

Cabbage 

Radish 

Carrot 

Pea 

Bean 

Pansy ' 

Phlox drnniinondii 

Tomato 

Watermelon 

Lettuce 

Average of all seeds 



Con- 
trol. 



91. 5 
88.5 
97.0 
92.4 
78.8 
82. 
95.7 
98.7 
53.0 
.53.9 
97.5 
99.0 
92.3 



86.77 



Mobile, 
Ala., 
Feb. 17 

to 
Nov. 6. 

202 
days. 



20.0 

12.0 

0.0 

17.0 

51.0 

8.5 

44.0 

0.0 

0.0 

0.0 

79.5 

64.0 

20.0 



24.31 



Baton 
Rouge, 

La., 
Feb. 17 

to 

Oct. 22. 

247 

days. 



88.0 
51. 2 
0.5 
25. 5 
.55. 5 
25. 
80.0 

•co.o 

0.0 

0.0 

9G.0 

92.0 

84.5 



50.86 



Dur- 
ham, 
N. H., 

Feb. 17 

to 
Oct. 26. 

251 
days. 



90.0 
82. 

0.0 
12.0 
59. 5 

2.0 
94.0 
78.0 

0.0 

0.5 
87.0 
82.0 
88.5 



52. 42 



Au- 
burn, 
Ala., 
Feb. 17 

to 

Nov. 19. 

275 

days. 



88.0 
62. 
12.0 
61. 5 
63. 
36.0 
97.9 
56.0 
2.0 
1.0 

91. 
86.0 
86.0 



57.34 



Lake 
City, 
Fla., 
Feb. 9 

to 
Oct. 1. 

234 
days. 



92.0 
77.0 
16. 5 
63. 5 
58. 5 
43.5 
86.5 
84.0 
1.5 
2.5 
94.0 
92.0 
85.0 



61.27 



Wag- 


San 


oner, 


Juan, 


Ind. T., 


P.R., 


Feb. 17 


Feb. 9 


to 


to 


Oct. 13. 


,Tune20. 


238 


129 


days. 


days. 


90.0 


92.0 


78.0 


78.0 


21.5 


50. 



70. 5 
60. 5 
49. 
80.0 
82. 
7.5 
5.5 
94.0 
94.0 
82.0 



62. 11 



7(;. 

62. 
48. 5 
98.0 
96.0 
6. 5 
11.5 
96. 5 
88. 
83. 5 



68.21 



Ann 
Arbor, 
Mich. 



98.0 
80.0 
97.5 
91.0 
77.5 
86. 
98.0 
100.0 
46.5 
40.0 
98. 
96.0 
92.5 



84. .58 



EFFECT OF CLIMATIC CONDITIONS. 1 7 

Kvoii thouoh the columns in ])oth Tables I and II are arrano(.(l in 
the order of the loss in vitality as shown by the averages of the 
various places, it will at once be seen that the relative degree of injury 
did not remain the same throughout the experiment. This is pro])ahIv 
best explained by a variation in the climatic influences. It is evident 
that in some of the places wdiere seeds were stored -the effects were 
more deleterious during the time between the first and second tests 
than the}' were during the first period of storage of 128 days. The 
results given in Table II are of the greater value in showing the 
relative merits of the different localities as places for storing seeds, 
extending as they do over a longer period of time. 

As a result of the second series of tests it was found that the average 
percentage of germination of all of the samples of seed that were 
stored in trade conditions at Mobile for 262 days was only 24.31 per cent. 
This is equivalent to a loss in vitalit}" of 71.98 per cent as compared 
with the average percentage of germination of the control samples, the 
average germination of the controls being 86.77 per cent. The pans}", 
phlox, onion, and beans stored at Mobile wholly lost their power of 
germination. The tomato seed, which proved to be the most resistant 
to unfavorable conditions, gave a germination of 79.5 per cent, or a 
loss in vitality of 18.16 per cent, as compared with the control sample, 
which germinated 97.5 per cent. The degree of deterioration in the 
seeds stored at the other places was much less marked than for those 
stored at Mobile. The loss in vitality was only 11.39 per cent in the 
seeds returned from Baton Rouge. The results from the seeds which 
were stored at Durham, Auburn, Lake City, Wagoner, and San Juan 
differed but little from ihose from Baton Rouge. The relative losses 
in vitality arc in the order given. The seeds kept in the packages 
which were stored under trade conditions in the laboratory at the 
University of Michigan showed a loss in vitality of only 2.52 per cent 
as compared with the control, the seeds of which were stored in a cool, 
dry closet on the fourth floor of the botanical laborator3\ Ordinarily 
a loss of 2.52 per cent would be considered as a normal variation due 
to sampling and testing, and such was probaldy true in these two sets, 
with the exception of the greater deterioration of the phlox, pansy, 
and ""'B" sweet corn, which were undoubtedly injured by the unfa- 
vorable trade conditions, as repeated tests have show n. 

From Table II it wdll also be seen that the "A" sweet corn, peas, 
tomato, and watermelon, with the exception of those returned from 
Mobile, show a fair percentage of germination. In some cases the final 
percentages of germination were even higher than the controls; but, as 
previously stated, the final germination is not ahvays a good criterion 
for the determination of vital it}', it being necessary to consider the 
germinative energy as a basis for comparison. In order to show this 
more fully some of the detailed results are herewith given in Tal)l(> III. 
These results show to a good advantage the degree to which germina- 
tion has been retarded. 
25037— No. 58—04 2 



18 THE VITALITY AND GERMINATION OF SEEDS. 

T.\iii,K III. — lictdnhiliini in (/n-inhialioii. due to hijiinj cdtised hij imfarorable (ihnatic 

conditions. 





Corn "A." 


Peas. 


Watermelon. 


Tomato. 


Place where secd.s 
were kept. 


Germi- 
nation 
at end 
of 64 
hours. 


Final 
germi- 
nation. 


Germi- 
nation 
at end 
of 40 
hours. 


Final 
germi- 
nation. 


Germi- 
nation 
at end 
of 84 
hours. 


Final 
germi- 
nation. 


Germi- 
nation 
at end 
of 83 
hours. 


Germi- 
nation 
at end 
of 107 
hours. 


Final 
germi- 
nation. 


Control 


Per cent. 
81.3 
4.0 
01.0 
50. 
64. 
68.0 
80.0 
80. 
82. 


Per cent. 
94.5 
20.0 
92.0 
88.0 
90.0 
92.0 
96.0 
88.0 
98.0 


Per cent. 
79.0 

a 24. 
60.0 
36.0 
36.0 
50.0 
54.0 

« 93. 7 
82. 


Per cent. 
95. 7 
41.0 
98. 
SO.O 
80.0 
SO. 
91. 
97.9 
98. 


Per cent. 

98.0 
0.0 

12.0 
0.0 
2.0 
0.0 
0.0 

22. 

91. 


Per cent. 
99.0 
04.0 
88.0 
92.0 
94.0 
92.0 
82.0 
86.0 
96.0 


Per cent. 
■ 78. 

1.5 
3S.5 

9.0 
40.0 
16.5 

0.5 
59.0 
7.5.5 


Per cent. 
92.7 

12.5 
78.0 
50. 
81.5 
0.5.0 
5. 5 
75. 5 
91.0 


Per cent. 
97.5 


Mobile, Ala 

San Juan, P. R 

Baton Rouge, La . . 
Wagoner, Ind. T .. 

Lake City, Fla 

Durham, N. H 

Auburn, Ala 

Ann Arbor, Mich.. 


79.5 
96.5 
96.0 
94.0 
94.0 
87.0 
94.0 
98.5 



a After 62 hours. 

In order that the results of Tables I and II may be more readil}' and 
f ulh' comprehended, it has been deemed advisable to summarize them 
in another table. For this purpose the average percentages of germi- 
nation of all of the different samples of seed have been determined for 
each of the different places. From these average percentages of ger- 
mination the deterioration in vitality, as shown })y both the first and 
second tests as given in Tables I and II, have been calculated, the ger- 
mination of the controls serving as a basis for comparison. These 
results furnish more trustworthv data as to the relative merits of the 
different localities as places for storing seeds. Likewise the per- 
centages of deterioration between the time of the first and the second 
tests are shown in Table IV. 

Table IV. — Average percentages of germination of all seeds kept at the various places, their 
deviations from the controls, and iJie increased percentages of loss in the second series of 
tests. 



Place of storage. 



Average germina- 
tion of all seeds 
used in experi- 
ments. 


Deterioration in 
vitality as com- 
pared with con- 
trols. 


First test. 


Second 

test. 


First test. 


Second 
test. 


Per cent. 


Per cent. 


Per cent. 


Per cent. 


87.79 
53.59 


86. 77 
24. 31 






38.95 


71.98 


...| 


08. 21 
'< 45. 18 


1 ''H 


21.39 
(' 47. 93 


80.48 


50.86 


8.32 


41.39 


85.57 


.52. 42 


2. .52 


39.58 


85.70 


57.34 


2.38 


33.91 


83.00 


61. 27 


5. 45 


29. 38 


82.12 


02. 11 


0. 45 


28. 41 


S6. 23 


84. .58 


1.77 


2.52 



Deterio- 
ration in 
vitality 
between 
first and 
second 
tests. 



Control 

Mobile, Ala. 



San Juan, P. R . 



Baton Rouge, La , 

Durham, N. H 

Auburn, Ala 

Lake City, Fla.... 
Wagoner, Ind. T . 
Ann Arbor, Mich. 



Per 



cent. 

1.10 
54.61 

9.20 
39.86 
36.81 
38.74 
33.10 
26.18 
24.37 

1.91 



a Calculated results. 



EFFECT OF CLIMATIC CONDITIONS. 19 

In Table IV the results are arranged in the order of the loss in vital- 
ity as shown by the second tests. However, a few words of explana- 
tion will be necessary, especially concerning the loss at San Juan. In 
the first place, the seeds were kept at San Juan onlj^ 131 davs" during 
the earl}' part of the summer, while during the most critical period, 
June 20 to November 6, they were in the botanical laboratory of the 
University of Michigan. Those marked Mobile, Ala., were, during 
the entire time, 262 days, under the influence of the warm, moist cli- 
mate of the Gulf of Mexico. The seeds kept at other places can well 
be compared with those from Mobile, the time being approximately 
the same. The average loss as shown b}^ the second tests was 3.35 
times greater than the loss in the first test, which by calculation would 
bring San Juan next below Mobile, with a loss of vital energy in the 
seeds equal to -IT. 93 per cent. But more data are necessary before 
such a gradation of injurious climatic influences can be established. 

Table IV, however, brings out another interesting point, as shown 
by comparing the results of the first and second tests at San Juan and 
Mobile. In the first test the loss in vitality of the seeds from Mobile 
was 38.95 per cent, while the seeds returned from San Juan showed a 
loss of only 14.31 per cent as compared with 71.98 and 21.39 per cent, 
respectively, as shown in Table II. The degree to which the seeds 
were injured while they were stored in San Juan was such that they 
continued to deteriorate much more rapidly than the control sample. 
This deterioration was most marked in the case of the pansy seed, the 
germination of the first test being 20 per cent and that of the second 
test only 6.5 per cent, showing a loss in vitality of 68.2 per cent and 
87.7 per cent, respectively. Thus when seeds are once placed in con- 
ditions unfavorable for the preservation of their vitality for a sufficient 
length of time to cause some injurj^, this injury will always be mani- 
fest and cause a premature death of the seeds even though they after- 
wards be removed to more favorable conditions. 

Seeds of strong vitality can withstand greater changes in conditions 
than seeds of low vitality without any marked deterioration. Through- 
out these experiments a wide difference has been observed between 
the "A" sweet corn and the "B" sweet corn. The original tests 
made January 30, 1900, at the time the seeds were received, showed a 
germination of 94 per cent for the "A" sample and 88 per cent for 
the "B" sample of corn. The control tests, made in November, 1900, 
showed a germination 0.5 per cent higher in each case; but the average 
loss in vitality of the two samples of seed kept at the various places 
was 12.17 per cent for the "A" sample and 26.10 per cent for the "B" 
sample. As with the pansy and the phlox these samples showed that 

« The number of days here given for San Juan is not absohitely correct. The time 
was reckoned from the date the seeds were sent from the laboratory until they were 
received in return. 



20 



THE VITALITY AND GERMINATION OF SEEDS. 



the stronger the vitality of the original sample of seed the more harsh 
treatment (;an be undergone witliout being- injured. Strong A'itality 
implies long life as well as vigorous seedlings. 

Another very important factor to be considered in the handling of 
seeds is the relative resistance of seeds of various species to adverse 
conditions. Certain seeds under one set of conditions may retain 
their vitality exceedingly well, while seeds of other species of plants 
under identical (,'onditions may he killed in a comparatively short time. 
For this reason no general rule can be laid down for the preservation 
of seeds. Table V shows the varying degrees of deterioration of the 
different species of seeds used in the experiments. 

Table V. — Differed degrees of deter ior(Uio)i. of various kinds of seeds. 



Kind of seed. 



Tomato 

Pea 

Corn, sweet, "A" . . 

Watermelon 

Lettuce 

Radish 

Corn, sweet, "B" . 

Bean 

Cabbage 

Carrot 

Onion 

Pansy 

Phlox drumiiiondii 



First test. 



Germi- 
nation of 
control. 



Per cent. 
95. 5 
95. 3 
95.9 
98.3 
81.6 
83.6 
89.3 
98.7 
92.7 
83.3 
95.8 
63.0 
69.0 



Average 
germi- 
nation 
from the 
various 
places. 



Per cent. 
93. 06 
91. 56 
94. 75 
97. 75 
SO. 00 
74. 38 
78. 10 
93. 00 
86. 00 
75. 16 
82.18 
38. 87 
44. 87 



Deterio- 
ration in 

vitality 

as com- 
pared 
Avith the 

control 
samples. 



Per cent. 
2.55 
3.92 
1.20 

.57 

1.96 

11.02 

12. 47 

5. 76 

7.22 

9.77 

15. 26 

38.33 

34. 97 



Second test. 



Germi- 
nation of 
control. 


Average 
germi- 
nation 
from the 
various 
places. 


Per cent. 


Per cent. 


97.5 


92. 43 


95.7 


84. 80 


94.5 


83.00 


99.0 


86.62 


92.3 


77.75 


78.8 


60.93 


,S8. 5 


65. 40 


98.7 


69. 50 


92.4 


52. 15 


82. 


37. 81 


97.0 


25. 12 


53.0 


8.00 


53.9 


7.62 



Deterio- 
ration in 
vitality 
as com- 
pared 
with the 
control 
samples. 



Per cent. 
5. 20 
11.39 
12. 17 
12.51 
15. 77 
22.67 
26. 10 
29. 58 
43.56 
53. 89 
74.10 
84.90 
85. 85 



In the above table the list of seeds is arranged in the order of their 
power to withstand the action of diverse climatic conditions, as shown 
by the results of the second test, given in Table II. Tomato seeds 
were found to be the most resistant, the control sample germinating 
97.5 per cent. The average germination of the samples of tomato seed 
kept at the various places was 92.43 per cent, or a loss in vitality of 
only 5.20 per cent. The seed showing the next least injury was the 
peas, with a deterioration of 11.39 per cent. The phlox, which was the 
most affected by the unfavorable conditions, germinated only 7.(52 per 
cent, thus showing a loss in vitality of 85.85 per cent. 

It is also interesting to note that the order, as shown by the second 
series of tests, is quite different from that of the first. This lack of 
uniformity increases the dilficulties that must be overcome before the 
causes of the loss of vitality in seeds can be fully comprehended. Were 
all seeds affected in the same way when subjected to identical con- 



EFFECT OF CLIMATIC CONDITIONS. 



21 



ditlons, the ordei- sliould have ivinained the .same throuo-hout, but the 
wide variation in atnio.s[)iieric changes ati'ects diU'erent seeds so very 
differently that no uniformity of results can be secured. For example, 
the conditions prevailing- from February until June were much more 
disastrous to the vitality of the tomato and pea than to the "A" sweet 
corn, watermelon, and lettuce, while the conditions existing from June 
to November were more injurious to the "A" sweet corn, watermelon, 
and lettuce. An examination of the table will show other results 
of a similar nature. During the earlier stages of devitalization seeds 
undergo a gradual deterioration in vitality, but after reaching a cer- 
tain stage in their decline there is a comparatively sudden falling off, 
and seeds, except perhaps a few of the most persistent, soon cease to 
show any power of germination. Such factors as these must be taken 
into account in determining the relative length of time that different 
kinds of seed will retain their vitality. But as yet sufficient informa- 
tion is lacking in order to make any trustworthy attempt to classify 
seeds in respect to their viable periods when subjected to different con- 
ditions. Numerous experiments are now under way, with the hope of 
furnishing a basis for such a classification. 

In order to obtain more data as to the influence of climate upon 
vitality additional samples of seed were sent to Mobile and Baton 
Rouge, where they were stored under the same trade conditions as for 
the former experiment. For these tests only cabbage, lettuce, and 
onion seeds, put up in envelopes, as for the previous tests, were used. 
The different packages of seed, placed in paper boxes from which 
they were not removed, were sent from the laboratorj^ on May 20, 
1901, and were returned November 26, 1901, the total time of storage 
being 190 days. The results of these tests are shown in Table VI, and 
are even more striking than those of the former tests shown in Tables 
I and II. 



Tahle VI. — ■Relative merits of Mobile, Ala., Baton Rouge, La., and Ann Arbor, Mich. 

as places for storing seeds. 

[Period, 190 days.] 





Cabbage. 


Lettuce. 


Onion. 


Seeds subjected to 
"Trade condi- 
tions." 


Percentage of seeds 
germinated at the 
end of— 


Percentage of seeds 
germinated at the 
end of— • 


Percentage of seeds germinated 
at the end of— 




36 
hours. 


60 
hours. 


14 
days. 


36 
hours. 


60 
hours. 


11 
days. 


60 
hours. 


84 
hours. 


108 
hours. 


14 
days. 


Mobile, Ala 

Baton Rouge, La . . 
Ann Arbor, Mich.. 


0.0 
0.0 
10.0 


0.0 
0.0 
04.5 


8.5 
•22. 5 
86.6 


0.0 
2.h 
07.0 


14.0 
3.".. r, 

82.5 


64.0 
74.0 
96.5 


0.0 
0.0 
3.0 


0.0 
0.0 
10.0 


0.0 
- 0.0 
43.0 


0.0 
0.0 
93.0 



Table VI shows quite clearly the deleterious action of the warm, 
moist climate of the Gulf of Mexico on the life of seeds. The onion 
seed which was stored at Mobile and Baton Kouge did not germinate, 



22 THE VITALITY AND GERMINATION OF SEEDS. 

while .seed from tlu' ,samc lot stored at Ann Arbor g-erniin:ited !)3 per 
cent. The cabbage seed was injured nearly as much as the onion, the 
sample from Mobile germinating- only 8.5 per cent. The conditions 
at Baton Rouge were slightl}^ more favorable to the preservation of 
vitalit}'. The cabbage seed stored at the latter place germinated 22.5 
per cent, while a like sample of seed stored at Ann Arbor germinated 
86.5 per cent. The lettuce was nmch more resistant than either the 
cabbage or the onion seed, but here, too, the injury was quite marked, 
especially as shown l)y the retardation in germination. The conditions 
at Mobile were also the most disastrous for the lettuce seed. During 
the first 36 hours that the tests were in the germinating chamber none 
of the lettuce seed from Mobile germinated, while the seed from the 
corresponding sample from Ann Arbor germinated 67 per cent. The 
final percentages of germination were 64 and 96.5 per cent, respectively, 
for the seed from Mobile and Ann Arbor, showing a loss in vitality of 
33.68 per cent in the seed stored at Mobile. Here it will be seen, as in 
Table V, that the onion seed was most sensitive and the lettuce seed 
most resistant to the unfavorable conditions. In the first tests shown 
in Table V the average loss in vitality of the lettuce, caljliage, and 
onion was 15.77, 43.56, and 74.10 per cent, respectively, while for the 
last tests, as shown in the foregoing table, the losses in vitality of 
similar samples of seed kept at Mo])ile were 33.68, 91.29, and 100 per 
cent, respectively. The ratio is practically the same in both cases, the 
loss in the cabbage seed being 2.7 times greater than that of the lettuce. 
The foregoing data are sufficient to indicate that climatic influences 
pla}' a very important part in the life of seeds, and that the degree of 
injury varies greatly indifferent places and likewise in different seeds. 
Some seeds were practically worthless after an exposure of four or five 
months in such places as Mobile, Baton Rouge, or San Juan, as shown 
in Table 1. After longer exposures, six or nine months, similar results 
were obtained from all of the places to which seeds were sent. Many 
of the seeds were killed, as shown in Table II. The conditions at 
Mobile were fatal to all of the seeds; that is, the seeds were worthless 
so far as the gardener is concerned. 

CAUSES OF THE LOSSES IN VITALITY IN DIFFERENT CLIMATES. 

Having shown that seeds lose their vitality nuich sooner in some 
localities than in others, the question naturally arises, ''Why this 
loss in vitality ? " Unfortunately only two of the places where seeds 
were stored. Mobile and San Juan, have Weather Bureau stations which 
are e({uipped for making complete observations of the meteorological 
conditions. It has l)ccn observed, however, that there is a very close 
relationship between the precipitation and the loss in vitality in seeds; 
that is to say, in a measure the loss in vitality is directly proportional 
to the amount of rainfall. This deterioration is more apparent as the 



CAUSER OF LOSSES IN VITALITY. 



28 



tempcvature increases, hut the injnry due to the increase in tempera- 
ture is dependent on the amount of moisture present. 

The following table has been compiled in order to show the ratio 
between the loss in vitalit}^ and the precipitation and temperature. 
The loss in vitality, as given in the second column of Table VII, rep- 
resents the average losses in percentages, calculated from the results 
of the germination tests of the 13 different samples of seeds, as shown 
in Table II. " 

The third column shows the annual precipitation in inches. The 
aniuial precipitation has been taken, because in some instances heavy 
rainfalls occurred just previous to the time that the seeds were put 
into storage. Then, too, the annual precipitation furnishes more accu- 
rate data for a basis of comparison. The mean temperatures, as given 
in column 4, are not the mean annual temperatures, but the averages 
covering the time during which the seeds were stored. The mean 
annual temperatures were not taken, chiefly for the reason that the 
critical period, in so far as temperature is concerned, is during the 
summer months. 

Table VII.- — lialio hehreen vildlit}/, precipitation, and temperatxire. ^ 



Place whore seeds were stored. 



Mobile, Ala 

Baton Rouge, La. 
Durham, N. H . . . 

Auburn, Ala 

Lake City, Fla . . . 
Wagoner, Ind. T . 
Ann Arbor, Mich 



Average 
loss in vi- 
tality of 
the 13 dif- 
ferent sam- 
ples of 
seeds. 



Pcv cent. 
71.98 
41.39 
39. .'■)8 
33. 91 
29. 38 
28.41 



Annual 
precipita- 
tion. 



Indies. 
91.18 
C6.37 
48.20 
(!2. 61 
49. 76 
42.40 
28. 58 



Temperature. 



Mean Fahr. 



Degrees. 
7L4 
72.2 
52.3 
64.4 
73.3 
67.1 
49. 12 



Maximum 

Fahr. 



Degrees. 
96.0 
98.0 
98.0 
98.0 
103.0 
107.0 
98.0 



I' These seeds were sent out in Fel)ruary, 1900, and were returned to the liotanical lal)oratory and 
tested in October and November, 1900. The average time that the seeds were kept at the various 
places was 252 days. 

''The results of the San Juan tests have been omitted from this table because, as has been previously 
stated, all of the seeds were returned from San Juan on June 20, 1900, when the first tests were made. 
The second .series of tests was made in October, 1900. During the time intervening between the first 
and second tests the San Juan samples were kept in the botanical laboratory at the University of 
Michigan. 

According to the table the seeds kept at Mobile suffered the greatest loss in vitality. However, it is 
quite probable that the greatest loss would have been from the seeds stored at San Juan had the time 
of storage been the same for the two places, so that the results of the San Juan tests could have been 
included in the table. This conclusion is based on the following facts: Normally, the number of rainy 
days at San Juan far exceeds those at Mobile. In 1900 there were 211 days on which rain fell in liun 
Juan, while the records for Mobile show only 140. Likewise the average temperature of the dew-point 
Tor San Juan was 71° F. and only 59° F. for Mobile, which, when expressed in terms of absolute 
moisture, gives 8.240 and 5. .5.55 grains of water per cubic foot at the time of saturation. On the other 
hand, the relative humidity of San Juan was 78.5 per cent, or slightly lower than that of Mobile, the 
latter having a relative humidity of 80.5 per cent. However, the mean annual temperatures were 
77.6° and 71.4° F., respectively, hence a mean absolute humidity of 7.099 grains of aqueous vapor for 
San Juan and only 0.718 grains per cubic foot for Mobile. 



24 



THE VITALITY AND GERMINATION OF SEEDS. 



From the forco-oino- table it will be seen that precipitation is a factor 
of much greater importance than temperature. In order to show the 
real value which- the amount of precipitation furnishes as a basis for 
judging the length of time that seeds will retain their vitality when 
stored in localities having a marked difference in the amount of rain- 
fall, the results set forth in the above table are represented diagram- 
matically as follows: 

Effect of jyrecipUation on vitolify. 



Place. 


Percentage of loss in 


vitality. 


Inches of precipitation. 


IMobilc 


71.98 




91. IS 






Baton Rouge 


41. 39 


GC. 37 






Durhiiiii 


39. r,,s 


48. 20 






Auburn 


33.91 


G2.61 






Lake City 


29. 3S 

•->s. II 


49. 71 i 






Wagoner 


42.4(1 






Ann Arljor 


2. .'i2 


28. TiS 










" 





A discrepancy is ver}" marked for Durham, N. H., which may be 
partially explained ))v considering again the conditions under which 
the seeds were stored. It will be remembered that these samples of 
seeds were stored in a hall which opened directly into a chemical labora- 
tory. It is quite probable that the low percentages of germination 
were due to the injurious action of gases emanating from the labora- 
tory. Of these gases, ammonia probabl}^ plaj^ed a very important part, 
as it is well known that seeds are very readily injured when subjected 
to the action of ammonia. 

It is to be understood that the above comparisons are somewhat 
indefinite. If the amount of rainfall were equally distributed through- 
out the year a definite ratio could, in all probability, ])e established; 
but in the majority of places there are alternating wet and dry seasons, 
whicli make such a comparison very difiicult and unsatisfactory. Yet 
for ordinary considei-ations it is sufficient to say that seeds will retain 
their vitality much ])etter in places having a small amount of rainfall. 
For more exact comparison other factors nnist l)e taken into account, 
especially the relati^'e hmuidity, mean temperature, and temperature 
of the dew-point, which ultimately resolves itself into the absolute 
amount of moisture present in the atmosphere. 

EFFECT OF MOISTURE AND TEMPERATURE UPON VITALITY. 

From tlic foregoing experiments it is quite evident tliat moisture 
plays an important part in bringing about the premature death of 
seeds and that the detrimental action of moisture is more marked as 



EFFECT OF MOISTURE AND TEMPERATURE. 25 

tho temperature increases. Formerly the general consensus of opinion 
has been to make this statement in the reverse order — that is, that 
temperature exerts a very harmful action on seeds if much moisture 
be present. For comparatively high temperatures the latter statement 
would probably suffice — at least it is not misleading, and in a certain 
measure it is true; but at the lowest known temperatures, as well as 
at ordinar}' temperatures, moisture is the controlling- factor, and in 
order to be consistent it should likewise be so considered for higher 
temperatures — that is, within reasonable limits. 

That temperature is only of secondar}' importance is brought out in 
the results obtained by a number of investigators. It has been well 
established by Sachs," Haberlandt,* Just,'' Krasau,'' Isidore-Pierre,^ 
Jodin,-^', Dixon, s' and others that most seeds, if dr}", are capable of 
germination after being- subjected to relatively high temperatures for 
periods of short duration. The maximum for most seeds is a tempera- 
ture of 100° C. for one hour; but if the seeds contain comparatively 
large quantities of moisture they are killed at much lower tempera- 
tures. It has been reported that lettuce seed will lose its vitalit}^ in 
two weeks in some of the tropical climates where moisture is abundant. 
Dixon has shown that if lettuce seed be dr}?^ it will not all be killed 
until the temperature has been raised to 114° C. 

In case of low temperatures the factor of moisture is of less impor- 
tance; yet even under such conditions the moisture must not be exces- 
sive or the injury will be quite apparent. But if seeds are well 
dried it can safely be said that they will not be killed as a result of 
short exposures to the lowest temperatures which have thus far been 
produced. Our knowledge of the resistance of seeds to extremel}" 
low temperatures is based on the experiments of Edwards and Colin, ^'^ 
Wartmann,' C. De Candolle and Pictet,-' Dewar and McKendrick,^" 
Pictet,^ C. De Candolle,'" Brown and Escombe,".Selby,^' and Thiselton- 

«Handbuch d. Exp. Phys. d. Pflanzen, Leipzig, 1865, p. 66. 

ftPflanzenbau I, 1875, pp. 109-117; Abs. in Bot. Jahresbr., 1875, p. 777. 

cBot. Zeit., 33, Jahrg. 1875, p. 52; Cohn's Beitriige zur Biol, der Pflanzen, 1877, 
2: 311-348. 

''Sitzungsbr. d. Wiener Akad. d. Wiss., 1873, 48: 195-208. I. Abth. 

''Ann. Agron., 1876, 2: 177-181; Abs. in Bot. .Tahresbr., 1876, II. Abtb., 4: 880. 

/Compt. Eend., 1899, 129: 893-894. 

f/ Nature, 1901, 64: 256-257; notes from the Botanical .School of Trinity College, 
Dublin, August, 1902, pp. 176-186. 

/'Ann. sci. nat. bot., ser. 2, 1834, 1: 257-270. 

« Arch. d. sci. phys. etnat., Geneve, 1860, 8: 277-279; ibid., ser. 3, 1881, 5: 340-344. 

ilbid., ser. 3, 1879, 2: 629-6.32; ibid., ser. 3, 1884, 11: 325-327. 

^Proc. Eoy. Inst., 1892, 12: 699. 

^ Arch. d. sci. phj-s. etnat., Geneve, ser. 4, 1893, 30: 293-314. 

'"Ibid., ser. 4, 1895, 33: 497-512. 

«Proc. Roy. Soc, 1897-8, 62: 160-165. 

^'Bul. Torr. Bot. Club., 1901, 28: 675-679. 



2(l THE VITALITY AND GERMINATION OF SEEDS. 

Dyer." la the experiments of the last-named investigator seeds were 
subjected to the temperature of liquid hydrogen (—250- to — 252'-'C.) 
for six hours, and when tested for vitality the germination was perfect 
and complete. '' 

Much more might be said on the effect of high and low temperatures 
on vitality. But for the commercial handling of seeds the extremes 
of temperature are of secondai-y importance and need not be further 
discussed at this time. In the present work the purpose has been to 
show the effect of moisture on the vitality of seeds when subjected to 
such temperatures as are usually met with in the storing of seeds. 

SEEDS TACKED IN ICE. 

On February 6, 1900, samples of each of thirteen kinds of seed 
were put up in duplicate, both in manila coin envelopes and in small 
bottles. The bottles were closed with carefully selected cork stoppers. 
These two sets of duplicate samples were then divided into two lots. 
Each lot contained one of each of the packages and one of each of the 
bottles of seeds. The samples thus prepared were carefully packed 
with excelsior in wooden boxes, the boxes l)eing then wrapped with 
heavy manila paper. In one of the boxes was also placed a Sixes' 
self-registering thermometer, so that the minimum temperature could 
be ascertained. 

These boxes were stored in a large ice house near Ann Arbor, being 
securely packed in with the ice at the time the house was being tilled. 
The first box was taken out with the ice on June 12, 1900, after a lapse 
of 126 days; The thermometer in this box registered a minimum of 
—3.6° C. It is safe to assume that this temperature was uniform, at 
least up to within a few days of the time when the seeds were taken 
out. Unfortunately, absence from the university at this particular 
time delayed an examination of the seeds until June 20. During the 
eight intervening days the box of seeds was kept in the laboratory 
and there many of the seeds in the packages molded, so that they were 
unfit for germination tests. In fact, the results of the tests from the 
paclcages are of little value within themsehes; but in comparison with 
the \'italit3' tests of the seeds kept in the bottles some important facts 
are l)rought out, and it has been deemed advisable to tabulate these 
results with those of the second series. 

The second box of seeds was packed approximately in the center of 
a large ice house (100 by 60 by 20 feet) and was taken out with the 
ice on July 21, 1900, after having been 167 days in cold storage. The 

«Proc. Roy. Soc, 1899, 65: 361-368. 

b Bra ssica alba (oily), Pisnm sativum (nitrogenout^), CucHrhiUi pepo (oily), Triticnm 
safivniit. (farinaceous), and Ilordeum vulgare (farinaceous). 



EFFECT OF MOISTURE AND TEMPERATURE. 



27 



box was broug-ht directly to the laboratory and tlie seeds were exam- 
ined at once. Those contained in the paper packages had absorl)ed a 
considerable quantity of moisture and were much softened. In all of 
the packages except those containing the onion and watermelon seeds 
some mold had developed; but in the seeds used for the germination 
tests care was taken to avoid using those that showed any trace of 
a mycelium, thereby reducing the injury due to fungous growth to a 
minimum, even though subsequent experiments have shown that such 
injuiy is practically negligible. 

An interesting point concerning the germination of some of the 
seeds at this low temperature may be stated in this connection. Eight 
of the peas, or i per cent, had already germinated, the radicles vary- 
ing in length from 1 to 2.5 cm., thus corroborating Uloth's results in 
germinating peas at or slightly below the temperature of melting ice.^' 

Table VIII. — The tntalily of seeds kept in an ice house in envelopes and bottles, and like- 
nise the vitality of the controls. 





First test, after 126 days. 


Second test, after 167 days. 




Germination. 


Differ- 
ence be- 
tween 
envel- 
ope and 
control 
sam- 
ples. 


Differ- 
ence be- 
tween 
envel- 
ope and 
bottled 
sam- 
ples. 


Germination. 


Differ- 
encebe- 
tween 
envel- 
ope and 
control 
sam- 
ples. 


Differ- 
ence be- 
tween 
envel- 
ope and 
bottled 
sam- 
ples. 


Kind of seed. 


Con- 
trol. 


Envel- 
ope. 


Bottle. 


Con- 
trol. 


Envel- 
ope. 


Bottle. 


Corn "A" 


Per ct. 
96.0 
90.0 
95.0 
93.5 
88.5 
79.5 
92.0 
100.0 
.52. 5 
74.0 

18. 
80.0 


Per ct. 
36.0 
60.0 
92.5 
89.0 

5.0 

73.0 
90.0 


Per ct. 
94.0 
96.0 
96.5 
94.0 
81.5 
80.0 
88.0 

100.0 
65.5 

"16.5 
93.5 

100.0 
66.0 


Per ct. 

00.0 

30.0 

2.5 

4.5 


Per cf. 

.58. 

30. 

4.0 

5.0 


Per ct. 
92.0 
92.0 
9.5.0 
92.0 
80. 5 
73.6 
94.7 

100.0 
52.0 
.54.0 
96.5 

100.0 
81.5 


Per cl. 
86.0 
74.0 
94.5 
90.0 
74.0 
52.0 
90.0 
0.0 
2.6 
11.0 
51.5 
90.0 
66.0 


Per ct. 
96.0 
94.0 
95. 
94.0 
89.0 
75. 5 
90.0 
98.0 
05.5 
08.5 
96.0 
100.0 
71.0 


Per ct. 

6.0 

18.0 

0.5 

2.0 

6.6 

21.6 

4.7 

100.0 

49.5 

43.0 

45. 

4.0 

15.5 


Per ct. 
10.0 
20 


Corn "B" 


Onion 


5 


Cabbage 

Radish 


4.0 
15.0 


Carrot 






23 5 


Pea 






6 


Bean 






98 


Pansy 


47.5 


60.5 


63 


Phlox 


57. 5 


Tomato 


22. 5 
8.0 


20. 5 
10.0 


44 5 


Watermelon 

Lettuce 


4.0 
5.0 










Average 


87.3 


63.6 


87.9 


25.0 


27.7 


84.9 


02.1 


87.6 


24.3 


27.0 



'« In making up the averages the result of the germination of the phlox was omitted because a sub- 
sequent examination showed that the bottle containing this sample of seed was broken at the bottom, 
thus admitting sufficient moisture to destroy vitality, as is borne out by the second test. 

The above table shows, as previously stated, that the results of the 
first tests are incomplete and not very satisfactory, owing to the fact 
that the germination tests were unavoidabl}^ delayed for eight days 
after the seeds were taken from the ice house; but with the second set 



a Flora, 1875, pp. 266-268. 



28 THE VITALITY AND GERMINATION OP SEEDS. 

of samples the counts for the vitality tests were beouii within an hour 
from the tiiue the seeds were removed from the ice house. Thus, the 
conclusions for these experiments must be drawn chief!}' from the sec- 
ond series of tests. However, comparisons wnll be made Avith the 
first where such seem justifiable. 

It will at once be seen that the seeds which were in paper packages 
gave a much lower percentage of germination than either the control 
samples or those kept in bottles. The average germination of the 
controls was S-t.O per cent, and the average germination of the seeds 
kept in bottles was 87.6 per cent, while onl}' 02. 1 percent of the seeds 
kept in paper packages germinated. This is equivalent to a loss in 
vitalit}' of 24.3 and 27 per cent, respectively, as compared with the 
vitality of the control samples and the samples from the bottles. The 
results of the first tests are practically the same, save that the difl'er- 
ences l)etween the control and the bottle samples are less marked. In 
the second case the a\'erage vitality of the seeds kept in envelopes was 
much reduced 1)}" the complete failure to germinate in the case of the 
))eans, which are most susceptible to the deleterious action of moisture 
at the given low temperature. 

One of the most important points brought out b}' these experiments 
is the result ol)tuined with onion, cabbage, and w atermelon seeds. In 
both the first and the second tests the germination varied but little 
throughout. However, in all cases the seeds in the paper packages 
were slightly injured by the action of the moisture. This factor is of 
much importance, especially in the case of the onion seed, which, 
when kept in a moist atmosphere at normal temperatures, soon loses 
its vitality', })ut when maintained at temperatures slightly below 
freezing it becomes very resistant to the action of moisture. The 
beans, on the other hand, were all killed, although they are ordinarily 
much more hardy than onion seed. It is quite probable, however, 
that the death of the l)eans may be attributed to the reduction in tem- 
perature. Containing as they do large quantities of starch, they 
absorl) more water than less starchy or more oily seeds. This factor, 
together with the large embryo, renders them much more susceptible 
to the injurious action of freezing temperatures. 

Another im])ortant feature brought out by these experiments was 
the better germination of the seeds which had been stored in bottles 
in the ice house. The average germination of these samples was 2.7 
per cent higher than that of the control. In a measure this may be 
included within the limits of variation; but when it is considered that 
all of the bottle samples except the beans, tomato, and lettuce showed a 
vitality equal to or greater than the control, it can hardl}' be considered 
as a normal variation, especially since only the lettuce gave an}^ marked 
variation in favor of the control. Likewise, the average percentages 



EFFECT OF MOISTURE AND TEMPERATURE. 29 

of the first series of tests show a slight increase in favor of the seeds 
kept in the bottles, though the increase is not so well marked and is 
less uniform than in those of the second series. 

Aside from the final germination there is still another factor that 
nuist be taken into consideration as bearing evidence of the advantage 
of keeping seeds at low temperatures, provided that they are kept dry. 
All of the samples that were stored in the ice house in ])ottles showed 
a marked acceleration in germination. It is quite evident that tlie res- 
piratory activities and accompanying chemical transformations were 
much reduced by the reduction in temperature, and the vital energy was 
thus conserved; but when the conditions were favorable for germination 
the greater amount of reserve energy in these seeds gave rise to a more 
vigorous activity within the cells and a corresponding acceleration in 
germination. 

Numerous other experiments showing the effect of moisture on tlie 
vitality of seeds were made. In contrast to those just given, the 
injurious action of moisture at higher temperatures, yet temperatures 
well within the limits of those ordinarily met with in the handling of 
seeds, will be next considered. 

EFFECT OF MOISTURE ON VITALITY AT HIGHER TEMPERATURES. 

This set of experiments was undertaken particularly to furnish con- 
ditions somewhat similar to those existing in the States bordering on 
the Gulf of Mexico, or, in fact, all places having a relatively high 
degree of humidity and a temperature ranging from 30^ to 37^ C. 
(SQ"^ to 98.6"^ F.) during the summer months. In order to secure the 
desired degrees of temperature two incubators were utilized, one being 
maintained at a temperature varying from 30° to 32° C, the other 
from 36° to 37"^ C. The thermo-regulators were so adjusted as to 
admit of a possible variation of nearly two degrees in each case. 

Beans, cabbage, carrot, lettuce, and onion were used for these tests. 
In each of the incubators the seeds were subjected to four different 
methods of treatment: 1. In a moist atmosphere, in free communica- 
tion with the outside air. 2. In a moist atmosphere, but not in con- 
tact with fresh air, the seeds being in sealed bottles of 250 cc. capacity. 

3. In a dry atmosphere, in free communication with the outside air. 

4. Air-dried seeds in sealed bottles. 

In order to obtain the conditions requisite for the first method of 
treatment, an apparatus was used as shown in figure 1. The seeds were 
put up in small packages and then placed in a 250 cc. bottle. The bottle 
containing the packages of seeds was placed withiii a specimen jar 
which was partially filled with water. This jar was then closed with 
a large cork stopper which carried two glass tubes, each of 1 cm. })ore. 
These tubes extended 25 cm. above the top of the jar and out through 



30 



THE VITALITY AND GEEMINATION OF SEEDS. 



^P 



the opening in tlie top of the ineulcitor. The primaiy object of the 
tub(^s was to prevent any water vapor from escaping within the incu- 
bator and thereby doing damage to the seeds that were to be kept dry 

in the same inculiator. For the same reason 
the cork in the jar was well coated with paraf- 
fin. Approximately the same volume of water 
was maintained in the jar throughout the ex- 
periment, more water being added through 
tube (U as occasion demanded, to replace the 
loss by evaporation. The chief advantage in 
having two tubes was the comparative ease 
with which the air within could be displaced 
by a fresh supply by forcing a current of fresh 
air through one or the other of the tubes. 

Two such preparations were made, one being 
left in the oven maintained at a temperature 
varying from 30^^ to 32^ 
C. , the other in the oven 
maintained at a tempera 
ture varying from 36° 
to 37"^ C. In both cases 
the bottles contained 
five packages of each of 
the live samples of seed, 
thus making provisions 
for testing at ditferent 
intervals. 

In order to supply the 
conditions for the second 
method of treatment, 
similar packages from the same samples of seeds 
were put into 8-ounce bottles, which were then 
kept for five days in a moist chamber. The in- 
crease in weight due to the absorption of water 
within the five da,ys was as follows: Beans, 3.03 
per cent; cabbage, 8.09 per cent; carrot, 8.26 per 
cent; lettuce, 7A5 per cent, and onion 8.43 per 
cent. This increase, with the water alread}' 
present in the air-dried seeds, gave a water con- 
tent of 13.23 per cent for the beans, 13.99 per 
cent for the cabbage, 13.60 per cent for the carrot, 
12.45 per cent for the lettuce, and 14.84 per cent 
for the onion. 

The bottles were then corked and sealed with paraffin, ))ut were so 




Fig. 1. — Apparatus used to de- 
termine the effect of moisture 
and temperature on the vitality 
of seeds in communication witli 
free air. 




Fig. 2.— Apparatus u.scd to 
determine the effect of mois- 
ture and temperature on the 
vitality of seeds not in com- 
munication with free air. 



EFFECT OF MOISTURE AND TEMPERATURE. 31 

constructed that the relative humidity of the inclosed air could be 
increased without the admission of more free air. The detailed con- 
struction of this apparatus is shown in fig. 2." 

The seeds continued to absorb moisture to a limited extent. In order 
that the inclosed air might l)e maintained at approximatel}' the same 
degree of saturation, a crude hygroscope was attached on the inside of 
each bottle. These hj^groscopes were made from awns of Stqm 
caplllata L., the tip of the awns being removed and a short piece of fine 
copper wire used as an indicator. These hygroscopes were suspended 
from the under side of the cork, as shown at /;, and by the side of each 
was suspended a fine fiber of silk, which, being carried around by the 
indicator, recorded the number of turns made by the awn. 

Five such preparations were made for each of the two sets, so as to 
furnish seeds for a series of tests. One set was kept at a temperature 
of 30^ to 32° C, the other at 36° to 37° C. The seed from one of the 
bottles, at each of the temperatures, was weighed after eighty-one 
days, at the time the germination tests were made. These weighings 
showed that at the lower temperatures the average increase in weight 
for all the seeds was 8.6 per cent, and at the higher temperatures, 6.3 
per cent. The increase in the case of the beans was quite marked at 
this time, being 13.3 per cent for those maintained at a temperature 
ranging from SO-* to 32° C, and 9.8 per cent for those maintained at 
36° to 37° C. 

The third set of conditions consisted simph" of packages of the air- 
dried seeds kept in open boxes in each of the incubators. This series 
of tests was made especially for the purpose of determining the effect 
of dry heat on the vitality of seeds when maintained at the tempera- 
tures above given for some considerable time. 

For the fourth series small packages of the seeds were put into 
2-ounce bottles, which were then corked and sealed with paraflin. Five 
of these bottles were kept in each of the ovens and germination tests 
were made at irregular intervals. The results of these tests furnish a 

« The wide-mouth bottle (5) contains the packages of seed (s). Through an open- 
ing in the cork is inserted a short piece of soft glass tubing, being first fused at the 
lower end and having a slight constriction drawn at c. At a distance of 1 cm. 
above the constriction is blown a small opening, as shown at o. A short piece of 
heavy rubber tubing if), cemented on a piece of heavy brass wire (tr), serves as a 
stopper. This stopper, which must fit closely within the glass tube, is operated by 
means of the heavy wire. When drawn up, the water in the tube may give off 
aqueous vapor, which can escape through the small opening (o) into the bottle. 
When suflicient moisture is present the supply is shut off by pushing the stopper 
down firmly against the constriction. The stopper must be well coated with vas- 
eline to prevent its sticking to the sides of the glass tube. To make the apparatus 
more secure against the entrance of fresh air, a second piece of rubber tubing ()■) 
is placed in the upper part of the glass tube, the top of whicli is then filled with oil. 



32 



THE VITALITY AND GERMINATION OF SEEDS. 



basis for comparing the relative merits of keeping- seeds in open vessels 
and in sealed bottles. 

Table IX will show the eft'ect of the various methods of treatment 
on the vitality of the seeds. 



Tahle IX. — Vitality of needs xvlien suhjected to the action of a dry and a moist atmosphere, 
both when exposed to free air and when confined in glass bottles, at relatively hiyli 
temperatures. « 



Kind of seed. 



Begin- 

niiiK of 
I'Xperi- 
merit. 



Bean Mar. 

Do do. 

Do do. 

Do ...do. 

Cabbage .do . 

Do I. ..do. 

Do I... do. 

Do ...do . 



Carrot. . 
Do . 
Do . 
Do . 

Lettuce 
Do . 
Do . 
Do . 

Onion . . 
Do . 
Do . 
Do . 



.do . 
.do. 
.do. 
-do . 



.do . 
.do. 
.do . 
.do. 

.do. 
.do. 
-do. 
.do. 



End of 
experi- 
ment and 
date of 
germina- 
tion tests. 



Apr. 4 

May 12 

May 24 

July 22 

Apr. 4 
May 12 
May 24 
Julv 22 



Dura- 
tion 
of ex- 
peri- 
ment. 



In open bot- 
tles, at tem- 
peratures 
varying 
from — 



30° to 36° to 30° to 36° to 
32°. 37°. 32°. 37°. 



Apr. 
May 
May 
July 

Apr. 
May 
May 

July 

Apr. 
May 
May 
July 



Days. 
31 
69 
81 
140 

31 

69 
81 
110 

31 
69 
81 
140 

31 

69 
81 
140 

31 
69 

81 
140 



Vitality of seeds when 
kept in a moist at- 
mosphere. 



In sealed 
bottles, at 

tempera- 
tures vary- 
ing from — 



P. cl. 
100.0 
97.5 
94. 
2.3 

87.8 
71.6 
80.0 
0.0 

83.5 

69. 5 

48. 

0.5 

92.5 

38.0 

55. 5 

0.0 

95.5 

68.0 

59.5 

0.0 



P.ct. 

100.0 

0.0 



90.5 
0.0 



77.5 
0.0 



90.5 
0.0 



89.0 
0.0 



P.ct. 

78.0 

75.0 

0.0 

0.0 

73.0 

30.0 

1.0 

0.0 

54. 5 

22. 5 

2.5 

0.5 

78.0 

44.5 

1.0 

1.5 

64.5 
2.5 
0.0 
0.0 



30° to 36° to 
32°. 37°. 



P.ct. 

44.0 
0.0 
0.0 
0.0 

72.5 
0.0 
0.0 
0.0 

29. 5 
0.5 
0.0 
0.0 

58.0 
2.0 
0.0 
0.0 

45.0 
0.0 
0.0 
0.0 



Vitality of seeds when 
kept in a dry atmos- 
phere. 



In open 
boxes, at 
tempera- 
tures vary- 
ing from — 



P.ct. 

86.0 
100.0 

98.0 
100.0 

86.5 
67.5 
89.0 
84.0 

84.5 
82.0 
44.5 
81.0 

91. 
42.0 
6.5.0 
82.0 

95.5 
97.0 
95.5 
90.0 



P.ct. 
84.0 
90.0 
90.0 
94.0 

84.0 
87.9 
92.0 
83.0 

88.0 
85.0 
50.0 
81.2 

86.5 
38.5 
58.5 
87.0 

93.0 
95.0 
94.0 
92.0 



In sealed 
bottles, at 

tempera- 
tures vary- 
ing from — 



30° to 36° to 
32°. 37°. 



P.ct. 

98.0 
92. 5 
98.0 
98.0 

83.5 
79.0 
92. 5 
88.5 

89.5 
83.5 
50.0 
78. 5 

91.5 
38.5 
62.5 
81.5 

96.0 
97. 5 
99.0 
97.5 



P.ct. 
98.0 
95.0 

100.0 
96.0 

86.9 
78.5 
92.0 
86.7 

89.0 
82.5 
48.0 
83.1 

90.0 
51.5 
67.0 
88.0 

97.5 
93.0 
95.0 
94.7 



Ger- 
mina- 
tion 
of 
con- 
trol 
sam- 
ples. 



P.ct. 
94.0 

98.7 
98.0 
99.4 

91.0 
83.0 
92.5 
93.1 

92.5 
78.0 
64.5 
83.1 

90.0 
31.5 
53.5 
79.9 

96.0 
98.5 
96.5 
95.4 



a A study of the table will show that the lettuce and carrot seed germinated very poorly at the end 
of 69 .ind 81 days. This, however, was not due to any inherent quality of the seed, but to an excess- 
ive temperature at the time the tests were made. Both of these seeds require a comparatively low 
temperature for tlieir suect'ssful germination, lettuce germinating best at 20° C, and carrot at an 
alternating temperature of from 20° to 30° C. 

The amount of moisture absorbed or expelled under the ditt'erent 
methods of treatment has an important bearing on the duration of 
vitality and will be considered briefly at this time. Only the g"cneral 
results will be disc-"s.sed in this connection, inasmuch as later experi- 
ments, carried out in a similar manner, show the detailed results to 
much better advantage. Nevertheless, it requires only a glance at 
the above table to show the marked difterence in the germinative 
power of seeds which have been stored in moist and in dry conditions. 
The seeds which were exposed in a moist atmosphere to the higher 



EB^FECT OF MOISTUKE AND TKMrEUATUKE. 83 

tenipciaturcs (36^ to 37'^ C) were killed much cai-lier than those 
subjected to the moist atmosphere at the lower temperatures — 30*^ to 
32^ C. — in both the open and the closed bottles, 

A weighing" at the end of 31 days showed that the average increase 
in weight of the seeds kept in the open, moist chamber, due to the 
absorption of moisture, was 6 per cent at a temperature of 30 to 
32"^' C, and 5 per cent at a temperature of Si}'^ to 37° C. For the 
seeds kept in the oven, maintained at the temperature of 30° to 32*-^ C, 
another weighing was made at the end of IS-i days, at wliich time the 
average increase in the water content had risen to 8.07 per cent. 
Unfortunately the seeds from the second oven, maintained at the 
higher temperature, had })ecome badl}^ molded in 09 da3^s, so that only 
the one weighing was made. 

Vitality tests made at this time, 69 days, showed that all of the 
seeds from the open, moist chamber, at the higher temperatures, had 
been previously killed as a result of the drastic treatment; conse- 
quently no future germination tests were made. Those maintained at 
the lower temperatures were almost entirely free from mold at the 
expiration of the experiment, only an occasional seed showing an}^ 
trace of fungous growth. Nevertheless, germination tests showed 
that the vitality had been destroyed in the cabl)age, lettuce, and onion. 
Beans and carrot were most resistant, the former having germinated 
2.3 per cent and the latter 0.5 per cent. All of the seeds had become 
very nuich softened. The beans and the lettuce had changed very 
materially in color, the beans (Early Kidney Wax Six Weeks) having 
become much darker and the lettuce (Black-Seeded Simpson) ahnost a 
lemon color. 

AVith the seeds constituting the second series, i. e. , in a tnolut atmos- 
phere Ijiit in sealed hottlea^ the injur}^ was much more severe. Here, as 
with the open chambers, the seeds sul)jected to the higher temperatures 
were killed tirst, even though the amount of moisture actually absor])ed 
was less, as was also true with the other series. A weighing made at 
the end of 81 da3"s gave an increase of 8.6 per cent for those from the 
oven maintained at a temperature of 30° to 32° C. , and 6.3 per cent at the 
higher temperature. Likewise, in this series, the seeds had become 
very much softened and a verj^ disagreeable odor had developed as a 
result of the putrefaction of their nitrogenous constituents. A close 
examination made at the end of 81 days revealed slight traces of fun- 
gous growth, but there is no reason to believe that these plaj'ed any 
part in the destruction of vitalit3^ However, in making counts for 
germination tests all molded seeds were carefully discarded. 

The results of the germination tests showed that the vitality of the 
seeds kept at the lower temperatures had been practically destroyed 
at this time. The beans and onions failed to germinate, while the 
25037— No. 58—04 3 



34 thp: vitality and okkmination of seeds. 

cabbtio'c, carrot, and lettuce germinated only i, li.5, and i per cent, 
respectively. 

During- the succeeding (JO days much mold had developed, and at 
the expiration of the experiment, 140 days,- only the carrot and the 
lettuce gave any indications of vitality. It is especially interesting to 
note with what rapidity the deterioration took place ])etween the sixt}'- 
ninth and the eighty-first days, showing that when vitality reaches a 
certain point in its decline there follows a comparativel}' sudden 
death. This same fact is also shown in the case of those seeds in this 
same series kept at the higher temperature. After 31 days' treatment 
the}^ all failed to germinate, except 0.5 per cent in carrot and 2 per 
cent in lettuce seeds. 

In the two series of experiments just considered there was an increase 
in water content as a result of the humidity of the air in wliich the 
seeds wore kept. But the third series, <jj}cji and dry^ presents (juite 
another factor. A weigliing made at the end of 30 days showed that 
there had been an average loss of 2.5 per cent for the lower tempera- 
tures and 3,5 per cent for higher temperatures. After this time the 
weight remained nearly constant. Subsequent experiments, which 
will l»e considered later, also show that the water capable of being 
expelled at any given atmospheric temperature is driven oil' in a com- 
paratively short time. In case of seeds this condition is practically 
completed in eight or ten days when maintained at temperatures as 
above given. This extra drying of the seed causes a greater contrac- 
tion of the seed coats, and in a number of cases a corresponding- 
retardation in the rapidity with which germination takes place. The 
retardation in the germinative activity is dependcMit on the increased 
difficulty with which the seeds al)sorb water, and in many cases has an 
important bearing on the vitality tests. 

The fourth and last series, in which the air-dried seeds were sealed 
in bottles and subjected to the temperatures at which the two ovens 
were maintained, gave still another very different set of conditions. 
Here there was also an increase in weight, due probal)ly to some 
process of oxidation, but the increase was very slight. The average 
increase from those kept at either of the temperatures was less than 
one-half of one per cent. 

Seeds, if well matured and thoroughly air-dried, are not injured 
when kept at temperatures below 37^ C, whether they be kept in free 
communication with fresh air, or in sealed l)ottles, or tubes. In the 
experiments under discussion the average percentage of germination 
was slightl}^ higher in the case of the seeds which had been stored in 
the sealed bottles. The mean percentage of germination for the seeds 
which had been exposed to the open air at a temperature of 30° to 
32° C. was 83.05 per cent. Those from the sealed bottles kept at the 
same temperature germinated 84.82 per cent. At the higher temper- 
atures — 36° to 37° C. — the mean germinationof the seeds from the open 



EFFECT OF MOISTURE AND TEMPERATURE. 35 

and the clo.sed bottles was 82.08 and 85.02 percent, respectively. The 
control sample terminated 85.45 per cent. That '67"^ C. is about the 
maximum temperature at which air-dried seeds can be stored without 
injury is shown by the following- experiments. 

Preparations similar to those al)ove mentioned were used, and after 
being subjected to a temperature of ST'^ C. for 219 days, there was no 
appreciable loss in vitalit}^, except the deterioration of -i per cent in 
the case of the cabbage seed that was kept in an open ])ottle, and 6.3 
per cent in the seed from a closed bottle." But by increasing the tem- 
perature, during an additional period of OS days, from 37° C. to a 
maxinuun of 44"" C, the injui-y was much more marked, especially in 
the closed bottles. In the open bottles the vitality of the cabbage was 
lowered from 91.3 per cent to 77 per cent, representing a loss in vital- 
ity of 15.06 per cent. The onion seed fell from 95.7 per cent to 87 
per cent when kept in an open bottle, and to 61 per cent when kept in 
a closed bottle. The beans showed no apparent injury in either case, 
except that they became very dry; consequently there was a retarda- 
tion in germination as a result of the slow absorption of water. 

The greater loss in vitality of the seeds kept in the bottles was the 
direct result of the higher humidity of the air inmiediately surrounding 
the seed, and not because there was a deficiency in the supply of fresh 
air, as might be readily assumed. In the open receptacles the additional 
amount of free water expelled, as a result of the increase in tempera- 
ture, was allowed to escape, while in the sealed l^ottles it only gave 
rise to a relatively moist atmosphere, and consequently to a premature 
death of some of the seeds. If seeds are to be so confined, thev should 
be previously dried at a temperature at which they are to be stored. 

All of these seeds had become very dr}' and brittle. The odor of 
the air confined within the sealed bottles had become very unpleasant; 
likewise there was a marked change in the color of the seed coats of 
the inclosed seeds. 

SUMMARY. 

Most seeds if kept dry are not injured by prolonged exposures to 
temperatures below 37'-^ C. (98. 6"^ F.), it being inunaterial whether they 
are in open or in sealed bottles. 

If the temperature be increased above 37° C, vitality is seriously 
reduced. 

If seeds are kept in a moist atmosphere, a temperature even as high 
as 30° C. {S6^ F.) works much injurj^ in a comparatively short period. 
'The degree of injury rapidly increases as the temperature rises. 

Provided the degree of saturation is the same, the deleterious effect 
of moisture is fully as great in open as in closed bottles. 

«Only cabbage, onion, and beans were used for this experiment, the carrot and 
the lettuce seed being omitted. 



36 THE VITALITY AND GERMINATION OF SEEDS. 

THE EFFECT OF DEFINITE QUANTITIES OF MOISTURE ON THE 
VITALITY OF SEEDS WHEN THEY ARE KEPT WITHIN CERTAIN 
KNOWN LIMITS OF TEMPERATURE. 

The result.s of the experiments just discussed furnish a fair criterion 
})y which to judge the vitality of seeds when iutiuenced ))y tempera- 
ture and moisture. It was still necessary to determine the effect of 
definite quantities of moisture on the vitality of seeds when they are 
submitted to temperatures well within the limits of that which may 
he encountered in counuercial transactions. 

On December 19, 1900, preparations were made to determine these 
factors. Seeds of cabbage, lettuce, onion, tomato, and peas were used 
for these experiments, which continued for 70 or 72 days. All of this 
seed was of the harvest of 1899 and had been in the laboratory during 
the eleven months immediately preceding the setting up of the experi- 
ments, being thus thoroughly air-dried. The amount of moisture 
present in the seeds at this time, as indicated by drying at 100*^ C, 
was as follows: Cabbage, 5,90 per cent; lettuce, 5 per cent; onion, 6.-11 
per cent; tomato, 1.71 per cent, and peas, 8.44 per cent. 

The preparations were made as follows: 

{a) Air-dried seeds were placed in bottles of 125 cc. capacity. The 
])ottles were closed with cotton plugs in order to protect the seeds 
from dust while permitting a free circulation of air. This set serv^ed 
largely as a check. 

(h) Air-dried seeds were carefully weighed and then put into 125 cc. 
bottles, closed with firm corks, and sealed with paraffin. 

((*, d, e, and f) These samples were also carefully weighed and 
scaled in bottles as h, but in the difierent series of bottles there was 
first introduced 0.5, 1, 2, and 3 cc. of water which had been previously 
absorbed by small strips of filter paper. 

{(j) The seeds constituting this series were first dried for 30 days at 
a temperature of from 30*^ to 32'-' C. and then put up in bottles which 
were sealed Avith paraffin. The loss in weight as a result of the dry- 
ing was as follows: Cab])age, 2.41 per cent; lettuce, 2,59 per cent; 
tomato, 2.71 per cent, and onion, 3.47 per cent, leaving a water con- 
tent of only 3.49 per cent, 2.41 per cent, 2 per cent, and 2.94 per cent, 
respectively. (Peas were not included in this series.) 

One of each of the above preparations was then subjected to difl'ereut 
degrees of temperature as follows: 

(1) Outdoor conditions, protected from rain and snow, but freely 
subject to all changes in temperature and humidit3^ The temperature 
during the time of the experiment, December 19, 1900, to February 28, 
1901, varied from a mininumi of —21.(3'^ C. to a maximum of 8.9"^ C. 

(2) In a fruit cellar having a comparatively low and uniform 
temperature ranging from 10'-' to 13'-' C 



I 



EFP'EOT OF DEFINITE QUANTITIES OF MOISTURE. 37 

(3) In the "dark room'"' of the botanical laboratoiy, which was 
quite dry and maintained at a temperature of 20° to 22° C. 

(4) In the herbarium room on the fourth floor of the botanical labo- 
ratory. The air here was very drj' and the mean temperature about 
the same as for No. 3, but with a much wider variation, reacliing at 
times a maximum of 30' and a minumum of 10° C. 

(5) In an incubator maintained at 30° to 32° C. 

(6) In an inculmtor maintained at 37° to 40° C. 

It will be observed that all of the preparations, except Nos. 1 and 4, 
were kept at temperatures which were quite uniform. The increase 
or decrease in the weight was determined at the expiration of 70 or 72 
days by again carefulh^ weighing the seed, after which germination 
tests were made. The results of tlie germination tests and the gain or 
loss in weieht are givxn in Table X. 



38 



THE VITALITY AND OKRMINATIOT^ OF REEBR. 



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40 THE VITALITY AND GERMINATION OF SEEDS. 

The fovoooiiio- tiiblo, showino- the conditions nndor which the seeds 
were kept, has been made quite complete. Aside from the linal per- 
centages of germination, the percentages of germination after a defi- 
nite numl)er of hours have likewise been given, the latter being better 
expressed as germinative energy. The germinative energy, as has been 
previously stated, is an important factor in determining the potential 
energy of a seed. This is quite clearly shown in many of the germi- 
nation tests recorded in the above table. The preliminary results show 
a marked contrast as a result of the different kinds of treatment, while 
the final I'esults reveal nothing more than the regular degree of varia- 
tion usuall}^ met with in testing seeds. Of the five species of seeds, the 
onion has yielded the most striking variations in the earlier stages of 
germination. Take, for example. No. 1535, the sample that was kept 
in an open bottle in the fruit cellar. The moisture absorbed was suffi- 
cient to cause a chemical transformation, which injured the vitalitv of 
the seed and consequently caused a retardation in germination. No. 
1539, the onion seed from the incubator maintained at a temperature 
of 37° to 40° C, germinated only 16.5 per cent in 77 hours, while 
the final percentage of germination was 95.5 per cent. Onion seeds 
Nos. 1532 and 1533 germinated in 77 hours 18.5 and 2.5 per cent 
respectively, while the final germination of the former was 93.5 per 
cent and of the latter 96 per cent. All of these tests gave final per- 
centag-es of germination somewhat higher than the mean of the control 
samples. But the germination was considerably retarded, the control 
samples having germinated 29.5 per cent during the first 77 hours. 
These retardations in germination must be due to a lowering of vitalit}^, 
as a more careful study of the table will show, and not to any excessive 
drying that ma}^ have taken place during the time of treatment. 
Numerous other examples are to be found in the ta]>le, some even 
more striking than those mentioned, but it is not deemed necessar}^ 
that they all be pointed out and discussed here. 

The table also shows the results of the various weighings made of all 
of the difl'erent samples which were kept in closed Ijottles. With but 
very few exceptions there was an increase in weight, which increase 
was quite marked in all cases where free water was introduced. The air- 
dried seeds that were sealed in bottles without the introduction of free 
water all increased slightlj^ in weight, with the exception of the peas, 
which showed a slight decrease in weight. It has been observed that 
the absolute loss in the weight of the peas was slightly greater than 
the total gain in the four other samples of seed. This, however, is 
not of sufficient uniformity throughout to fully justify the conclusion 
that cabbage, lettuce, onion, and tomato seed have a greater affinity for 
water than peas, and that the former ro))bed the latter of a portion of 
their water content. Yet a portion of the increased weight of the 
cabbage, lettuce, onion, and tomato seed is ])r()])ab1v b(>st accounted 



EFFECT OF DEFINITE QUANTITIES OF MOISTURE. 41 

for in that way. On the other hand, it is quite prol»al)U^ tiiat a ]K)r- 
tion of the increase in weight was due to the results of intraniolecuhir 
transformations and to the coexistent respiratory activities of tlie 
seed. The means of making these determinations are far from easy. 
Van Tieghem and G. Bonnier have shown" that seeds kept in sealed 
tubes in atmospheric air increased in weight during two years, but the 
increase was very small. In their experiments the peas which were 
in sealed tubes increased tjI^ of their original weight, A corresponding 
sample kept in the open air increased ,V of its original weight. 

Nos. 1510 to 1515 in Table X show an increased weight in seeds 
when sealed in bottles for TO days. These seeds were previously 
dried for 30 days at a temperature of 30° to 32° 0. Disregarding the 
increase in weights as aliove given and the factors to which such 
increase may be attributed, it is quite evident that in all cases where 
water was added the increase in weight was due chiefly to the absorp- 
tion of the water. The absolute increase was approximately the same 
as the w^eight of the water added. 

The amount of water absorbed by different seeds varies greatly 
under identical conditions, depending largely upon the nature of the 
seed coats and the composition of the seed. The average increase in 
weight of the seeds used in these experiments was as follows: Onion, 
6.27 per cent; pea, 5.51 per cent; cabbage, 4.12 percent; lettuce, 3.99 
per cent; tomato, 3.99 per cent. The loss in vitality of the corre- 
sponding samples was 28, 12, 23.7, 18.5, and 11.7 per cent, respec- 
tively. The relationship here is quite close, the amount of water 
absorbed being roughly proportional to the loss in vitalit3^ The 
peas, however, afford an exception to this general statement. But it 
must be remembered that peas require a much larger percentage of 
moisture to start germination and are likewise capa])le of undergoing 
much wider variations than the other seeds in question. However, 
before a definite ratio can be established between the al)Sorption of 
water and the loss in vitality, many other factors nmst be taken into 
consideration, such as the composition, water content, and duration of 
vitality of the seed under natural conditions. 

Another interesting factor is shown in No. 1516 of Table X. These 
seeds were dried for 30 days at a temperature of 30° to 32° C, after 
which they were kept in an open bottle in the laboratory for 10 days. 
During the 30 days' drying the ca])bage lost 2.41 percent, lettuce 2.59 
per cent, tomato 2.71 per cent, and the onion 3.47 per cent of moisture. 
These same seeds when exposed to the free air of the laborator}^ for 40 
days never regained their original weight, the increase being as follows: 
Cal)])age, 0.6 per cent; lettuce, 0.58 per cent; tomato, 1.56 per cent; 
onion, 0.89 per cent. The average quantity of water expelled was 2.79 

«Bul. 8oc. bot. France, 29: 25-29, 149-158, 1882. 



42 THE VITALITY AND OERMTNATION OF SEEDS. 

per cent in 30 da3's, while the average increase in weight during- the 40 
days was onl}^ 0.91 per cent. These results show that if seeds are once 
carefully and thoroughly dried, they will remain so; that is, if kept in 
a comparatively dry room. This is an important factor in the preser- 
vation of vitality, as is l)orne out in the results of the germination 
tests. Later experiments were made wdth ver}' similar results, and an 
analogous method of treatment promises to be of much value as a 
preliminary handling of seeds. It is not definitely known to what this 
stronger vitalit}' is due, whether it be simply to the effect of the dry- 
ing or to some process of chemical transformation which makes the 
seeds more viable. These results are now under consideration and will 
be reported at some future time. 

The table also shows in a very striking degree the decrease in the 
numl)er of germinable seeds with an increase in the moisture and 
temperature. The amount of moisture absorbed by the seeds, with a 
limited amount present in the bottles, was inversely proportional to the 
temperature. At the higher temperatures the inclosed aii- held a larger 
portion as water vapor; however, there was a greater deterioration in 
vitality. Where the seeds were kept outdoors at the low" temperatures 
(—21.6° to 8.9° C.) of the winter months, no injury was apparent 
except where 3 cc. of water was added, and then onl}^ the onion seed 
was affected. This sample of seed had absorbed a quantit}" of water 
ecjual to 10.38 per cent of the original weight, which together with 
the original water content (6.41 per cent of the original sample) made 
IY.88 per cent of moisture in the seed. Practically the same results 
were obtained with the seeds kept in a fruit cellar at a temperature of 
10° to 13° C. The samples of this series, in the open l)ottles, were 
also injured, as has been pointed out. With the samples that were 
stored in the dark room and in the herbarium room, the injury was 
more marked as a result of the higher ten>perature; })ut even here the 
seeds in the bottles which contained 0.5 cc. of free water deteriorated 
very little. The injury was confined to the onion seed, which showed 
a slight retardation in germination. Where 1 cc. , 2 cc. , and 3 cc. of 
water were added, vitality in some instances was likewise remarkably 
well preserved. The lettuce, tomato, and peas gave no indications of 
any deterioration save in the bottles containing 3 cc. of water. Here 
the lettuce and peas were permanently injured, while the tomato seeds 
sufi'ered only sufficiently to cause a delay in the rapidit}' with which 
they germinated. The calibage seed was retarded with 2 cc. and a 
lowering of the final percentage of germination with 3 cc. of water. 
The onion seed, being very sensitive to these unfavoi'able conditions, 
deteriorated very greatly, being practically worthless where 3 cc. of 
water were added. A brief study of the table will readily show that 
many seeds were killed at the still higher temperatures of 30° to 32° 
C. and 37 to 40° C The onion seed was slightly injured even where 



EFFECT OF DEFINITE QUANTITIES OF MOISTURE. 43 

no water was added. However, a temperature of 40^^ C. is sunici(Mit 
to injure many seeds, even thoug-h the lil)erated water be permitted to 
escape, as is shown in the tests of the onion, No. 1539 of the talde. 
The greatest injiuy when air-dried seeds are sealed in bottles and tlien 
subjected to a higher temperature is due to the increased humidity of 
the confined air, as a result of the water liberated from the seeds. 

At first glance some of the conditions given in the above tal)le may 
seem to be extreme and far beyond any normal conditions that would 
be encountered in the ordinary handling' of seeds. This may seem to 
be especially true with the seeds kept in the bottles with 3 cc. of 
water where the additional amount of moisture absorbed gave rise, in 
some of the seeds, to a water content of approximateh^ 20 per cent. 
Yet this need not be thought of as an exception, for such extreme 
cases are often encountered in the commercial handling of seeds. 
During the process of curing' even more drastic treatment is not 
infrequently met with. Pieters and Brown ^' have shown that the 
common methods emploj^ed in the harvesting and curing of Poa pra- 
tensis L. were such that the interior of the ricks reached a tempera- 
ture of 130° to 140° F. (.54.4° to 60° C.) in less than sixteen hours, at 
which temperature the vitalit}^ of the seed is greatly damag'ed and 
frequently entirely destroyed. The interior of one rick reached a 
temperature of 148° F. (64.4° C.) in twent}^ hours, and the vitality 
had decreased from 91 per cent to 3 per cent, as shown l)y the ger- 
mination of samples taken simultaneously from the top and from the 
inside of the same rick. 

On the other hand, the extreme cases need not ))e considered. 
Take, for example, the onion seed that was sealed in a ])ottle with 
1 cc. of water and maintained at a temperature of 37° to 40'^ C. Tlie 
increase in weight due to the water absorbed was 3.91 per cent, thus 
giving a moisture content of 11.2 per cent and a complete destruction 
of vitalit}". The cabbage seed, kept in the same bottle, had absorbed 
a quantity of water equivalent to 2.35 per cent of its original weight, 
which, with the 5.90 per cent contained in the original sample, gav^e 
8.25 per cent of water. This sample of seed germinated only 11 per 
cent, having thus no economic value. In neither of these samples 
was the amount of water present in the seeds greater than that ordi- 
narily found in commercial samples. Moreover, the temperature was 
much below that frequently met with in places where seeds are 
offered for sale and likewise well within the limits of the maximum 
temperature of our summer months, especially in the Southern 
States. Take, by way of comparison, the maximum temperatures of 
some of the places at which seeds were stored to determine the effect 
of climate on vitality, as shown in another part of this paper. During 



« Bulletin 19, Bureau of Plant Industry, U. 8. Department of Agriculture, 1902. 



44 



THE VITALITY AND GERMINATION OF SEEDS. 



the summer of 1900 the maximum temperature at Wag-oner, Ind. T., 
was 107° F. (41.1° C), while that of Lake City, Fla., was 103° F. 
(39.5° C). If these points are kept in mind, it is not at all surpris- 
ing to find that seeds lose their vitality within a few weeks or months 
in warm, moist climates. 

In order to make the abov^e facts more clear the preceding table has 
been summarized and is presented in the following condensed form, 
showing the relation of the water content of the seed to vitalit}^: 

Table XI. — Marled dek'r I oration in vitality with an increase in the qiinntity of the imler 

content of seeds. 



How preparations were made. 


Amount of water 

introiliicecl inli) 

the l»ottk-s. 


Average in- 

erease in 

weight as a 

rt'sult of the 

greater water 

content. 


Average 
moisture in 
.seeds at the 
time germi- 
nation tests 
were made. 


Average 
germina- 
tion. 


Control sample 


cr. 


Per cent. 


Per crnt. 
6.07 

'1 2. 77 

G. .55 

8.31 

9.91 

12.75 

1.5. 10 


Per cent. 
93.3 


Closed bottles, sealed with paraffin 

Do 


Water expelled. 
None. 
0.5 
1.0 
2.0 
3.0 


0. 06 
.08 
1.75 
3.24 
.5.91 
8.13 


a 93. 9 
94.0 


Do 

Do 


91.7 
83.3 


Do 

Do 


67. 5 

,58. 6 







a Peas not included in this set. 

Numerous other results of a similar character might be cited, l)ut it 
hardly seems necessary at this time, since there can be no doubt that 
moisture is the prime factor in causing the premature destruction of 
vitality in seeds in the usual conditions of storage. Wh}' they lose 
their vitality as a result of the unfavorable conditions is quite a differ- 
ent question, and has to do wnth the very complex composition of the 
seed. 

A COMPARISON OF METHODS OF STORING AND SHIPPING SEEDS 
IN ORDER TO PROTECT THEM FROM MOISTURE AND CONSE- 
QUENTLY TO INSURE A BETTER PRESERVATION OF VITALITY. 

SUGGESTIONS OF EARLIER INVESTKJATORS. 

As early as 1S32, Aug. Pyr. De Candolle" wrote a chapter on the 
conservation of seeds, in which he said that if seeds be protected from 
moisture, heat, and oxygen, which are necessarv for germination, 
their vitality \\\\\ be nnich prolonged; moreover, that if seeds are 
buried sufficiently deep in the soil, so that they are protected at all 
times from the very great influence of oxygen and moisture, their 
vitality will be preserved for a much longer period. 



"Physiologie Vegetale, Paris, 1832, Tome II, p. 618. 



COMPARISON OF METHODS OF STORING AND SHIPPING. 45 

Gii;lioU" goes so far as to say: 

There is no reason for denying the possibility of tlie retention of vitality in seeds 
preserved during many centuries, such as the Mummy wheat and seeds from Pompeii 
and llerculaneum, provided that these seeds have been preserved from the begin- 
ning in conditions unfavorable to chemical change. * * * The original dryness 
of the seeds and their preservation from moisture or moist air must be the very 
first (conditions for a latent secular vitality. 

Some of the earliest suggestions for storing seeds in quantity were 
made })y Clement and Fazy-Pasteur, and were reported by Aug. IVr. 
De Candolle in his Physiologie Vegetale. Clement suggested the use 
of large cast-iron i-eceptacles, made impervious to air and water, the 
well-dried seeds to ])e poured in through an opening at the top, after 
which the opening should be hermeticall}' sealed and the seeds with- 
drawn through an iron pipe and stopcock at the bottom of the tank. 
The scheme of Faz3^-Pasteiu' was to store seeds in wooden boxes well 
covered with tar. This method was especially applicable to small 
([uantities of seeds, and was used to a limited extent at that time, but, 
so far as has been ascertained, it has long since been discarded. The 
keeping of seeds in large iron tanks, as suggested by Clement, has 
never l>een practiced to any extent. It seems quite possible, however, 
that the present "tank" grain elevator, now so itniversally used, might 
readily l)e modified in such a way as to make the method suggested ])y 
Clement quite practicable. 

THE NECESSITY FOR THOROUGHLY CURING AND DRYING SEEDS. 

In addition to being well matured and carefully harvested, seeds 
should be thoroughly cured and dried before being put into the stor- 
age bins. Much better results would be obtained if .such seeds were 
artilicially dried for several days in a current of dry air at a tempera- 
ture not to exceed 35*^ C. With this method of drying, from 2 to 4 
per cent of the moisture usually present in air-dried seeds is expelled. 
The accompanying contraction of the seed coats makes them more 
impervious to the action of moisture, and consequently the seeds are 
better prepared for storing and shipping. Experiments made with 
cabbage, lettuce, onion, and tomato seeds gave results as follows: The 
average loss in weight of the air-dried seeds, after an additional dry- 
ing of 30 days at a temperature of 30"-^ to 32° C. was 2.79 per cent. 
Yet these same seeds, when kept for 40 days in the laborator}^ reab- 
sorbed only an average of 0.91 per cent of moisture. Like quantities 
from the original sample gave onl}^ the slight variations ordinarily met 
with, due to the humidity of the atmosphere. Thus seeds, when once 
carefully and thoroughly dried, will not regain their original weight, 
provided they be kept in a dry room. 

a Nature, 1895, 52: 544-515. 



46 THE VITALITY AND GERMINATION OF SEEDS. 

CIIAKACTEli OF THE SKEU WAREHOUSE OK STOKAtiE ROOM. 

Another important factor in the .storing- of seeds is the character of 
the seed warehouse or storage room. The first point to be considered 
is dryness. Such houses should be kept as dry as possible, which can 
be accomplished either by means of artificial heat or by the use of 
strong drying agents, or better still, by l)oth. True, if the seed ware- 
house be located in a section having a dr}' climate, this ditiiculty is at 
once largely overcome. But in man 3^ cases such a location is imprac- 
ticable or even impossible, and other means must be resorted to. As 
a matter of fact, most large seed warehouses are not heated and a 
great loss in vitality inevitably folloAvs; but each seedsman nmst 
determine for himself whether or not this loss is sufficiently great to 
justify the expense of heating- such a storage room. 

Experiments carried on during- the progress of this work have 
shown some very marked differences in favor of seeds stored in rooms 
artificiall}' heated. The averages of the thirteen samples of seeds from 
the eight places at which they were stored show a difi'erence in the 
loss of vitality of 9.87 per cent. Those kept in rooms that were arti- 
ficially heated during- a greater portion of the time deteriorated 25.91 
per cent, while those stored in rooms not so heated deteriorated 35.78 
per cent. The loss here given for seeds stored in dry rooms is greater 
than such conditions warrant, owing to the very unfavorable condi- 
tions at Mobile, Ala,, and Baton Kouge, La. At Lake City, Fla., the 
relative percentages of deterioration Avere 29.42 and 16.27 for the 
unheated and heated rooms, respectively; at Auburn, Ala., 33.90 and 
10.31 per cent, and at Durham, N. H., 39.58 and 3.57 per cent, respec- 
tively. Unfortunately these experiments were not made with this 
definite point in view, and the results are not entirely satisfactory, as 
no records were made of the temperatures and humidities. 

THE VALUE OF GOOD SEED TO THE MARKET GARDENER. 

This work was undertaken chiefl}^ for the purpose of finding some 
improved methods of shipping and storing seeds in small packages, 
wherein their vitality might be better preserved. The rapid deterio- 
ration in vitality causes great losses to gardeners living in districts 
where the climatic conditions bring about the premature destruction 
of vitality in seeds. In many cases the seeds are practically worthless 
or altogether fail to germinate after a few weeks' exposure. The loss 
in such cases is not in the greater quantity of seed reqviired, but the 
retardation or complete failure of the germination often means delay, 
making the difference between success and failure in the desired crop. 
Seed of low vitality is even worse than dead seed. With the latter the 
difficulty is soon discovered, while with the former, although the seed 
will germinate, the seedlings are not sufficiently vigorous to develop 



COMPARISON OK METHODS OF STORING AND SIIIITINO. 47 

into strono- and heiilthy plants. True, most enterprising gardeners 
usually have vitality tests made inmiediately preparatory to planting, 
but this is not always convenient, and they rely on the results of tests 
made at some earlier date. In such cases it quite frequently hai)pcns 
that they accept the results of tests made several weeks earlier. With 
many seeds this will suffice, yet there are many others that will dete- 
riorate very materially w ithin a few weeks or even within a few days 
in such unfavorable climates as exist, for example, near the Gulf of 
Mexico. In a letter dated January 15, 1903, Mr. J. Stecklcr, of New 
Orleans, La., wrote as follows concerning the vitality of seeds: 

Some seeds are not worth being planted after being here three months. This is 
especially true of eaulitlower seed. We have made repeated tests and this seed after 
remaining here 90 days was worthless and had to be thrown away. 

SHIPPING SEEDS IN CIIAKCOAL, MOSS, ETC. 

Bornemann" made some experiments with seeds of Vtctorui n'(/!a 
and Enryale fcrox, in which he found that when packed in powderi^l 
charcoal they soon lost their vitality, but Avhen packed in powdered 
chalk slightl}^ better results were obtained. On the other hand, 
Dammer* recommends powdered charcoal as a method of packing for 
seeds that lose their vitality during shipment, especially the seeds of 
palms and a number of the conifers. 

Charcoal is undoubtedly much better than moist earth or moss, 
which are frequently used, the latter ali'ording abundant opportunities 
for the development of molds and bacteria during transit. Some such 
method as moist charcoal is necessary in case of seeds which lose their 
vitality on becoming dry. Numerous other reports have been published 
from time to time concerning the shipping of seeds of aquatic plants, 
as well as those of low vitalit}^, but they need not be discussed further 
at this time. 

NATURE OF THE EXPERI3IENTS. 

Aside from some popular accounts and miscellaneous suggestions, 
but little has been done toward finding improved methods of shipping 
and storing seeds of our common plants of the garden and field. 
Accordingly, in February, 1900, a series of experiments was under- 
taken to determine some of these factors, in which three questions 
were considered: (1) How ma}^ small quantities of seeds be put up so 
as to retain a maximum germiuative energy for the greatest length of 
time? (2) What immediate external conditions are best suited for the 
longevity of seeds? (3) What part do climatic conditions pkw in 
affecting the life of seeds ? 

« Gartenflora, 35. Jahrg., 1886, pp. 532-534. 
&Ztschr. trop. Landw., Bd. I, 1897, No. 2. 



48 THE VITALITY AND GERMINATION OF SEEDS. 

In order to answer the tirst question, duplicate samples of the various 
kinds of seeds were put up in double manila coin envelopes, as 
described on page 1-i. Likewise, duplicate samples were put up in 
small bottles, the bottles being closed with good cork stoppers. Some 
of the bottles were filled with seed, while others were only partl}^ full. 
In some cases there was a surplus air space five times as great as the 
volume of the inclosed seeds. This space, however, had no bearing 
on the vitality of the seeds as far as could l)e determined. 

In order to determine what immediate external conditions play an 
important part in the destruction of vitality, samples of seed, ])repared 
as above described, were stored in difl'erent places." At each place 
they were subjected to three dift'erent conditions of storage, which, for 
convenience, have been designated as "trade conditions,'" "dry room," 
and " basement," as described on page 14. In addition to these three 
methods of storage, numerous other conditions were tried in and near 
the laboratory; such as in incubators at increased temperatures and with 
var3dng degrees of moisture, in cold storage, in greenhouses, and in 
various gases, in vacuo, in liquids, etc. 

The third question, " What part do climatic conditions play in aifect- 
ing the life of seeds F' has been answered for the most part in a dis- 
cussion on the efl^ect of climate on vitality, page 13. In fact, the seeds 
in the envelopes kept under trade conditions were the same in both 
cases, being used here simply as a means for comparing the vitality of 
seeds when stored in paper packages and in bottles, as well as to show 
the relative merits of trade conditions, dry rooms, and basements as 
storage places for seeds. 

DISPOSITION OF THE SAMPLES.* 

A more definite description of the treatment given the seeds in the 
various places may be summed up as follows: 

San Juan, P. R. — The seeds were sent to San Juan on February 9, 
1000, and were returned on June 20, 1900, after a lapse of 131 days.^ 
At San Juan the seeds were stored under trade conditions only, and 
the various packages were not removed from the original box in which 
they were sent. While in San Juan the box containing the seeds was 
kept in a room well exposed to climatic influences, being protected 
only from the direct rays of the sun and from rain. 

« San Juan, P. R. ; Lake City, Fla. ; Mobile, Ala. ; Auburn, Ala. ; Baton Eouge, La. ; 
Wagoner, Ind. T. ; Durham, N. H., and Ann Arbor, Mich. 

'' The places of storage represented by trade conditions have already been described 
for each of the localities, but it seems advisable to rewrite the descriptions here so 
that they may be more readily compared with the dry room and ])asement conditions. 

t-'The exact time that the seeds remained at San Juan was much less than 131 days, 
the time of transportation being included, as has l)een done for the other places. 



COMPAKISON OF METHODS OF STORING AND SHIPPING. 49 

Lahe C'dy^ Fla. — The .seeds were sent to Lake City on February 9, 
19U0. The first complete set was returned on June 18, after 129 days. 
The second complete set was returned October 1, after 234 days. The 
"trade conditions" at Lake City were supplied by keepino- the seeds 
in a small, one-story frame building, the doors of which were open the 
greater part of the time. This building was not heated, and the seeds 
were stored approximately 5 feet from the ground. "Dry room" 
conditions were those of a storage room on the fourth tloor of the 
main building of the Florida Agricultural College. The third set was 
kept in a small bulletin room in the basement of the same building. 

2Iohlle, Ala. — The seeds were sent to Mobile on February 17, 19U0. 
One set was received in return on July 7, after 180 days. The other 
set was received on November 6, after 262 days. The "trade condi- 
tions " in this case consisted of a comparatively open attic in a one-story 
frame dwelling. The set in a "dry room" was kept in a kitchen on a 
shelf 5 feet from the floor, and not more than 6 feet distant from the 
stove. Here they were subjected to the action of artilicial heat through- 
out the entire period. '^ The seeds under "basement" conditions were 
kept in a small collar, which during the season of 1900 was very moist. 

Auhurn, Ala. — The seeds were sent to Auburn on February 17, 
1900. The first complete set was received in return on May 30, the 
second on November 19 of the same year, or after 1()2 and 275 days, 
respectivel3\ " Trade conditions " consisted of an office room connected 
with a greenhouse, with the doors frequently standing open; "dry 
room" conditions w^ere obtained in the culture room of the biological 
laboratory on the third floor of the main building of the Alabama 
Polytechnic Institute, " })asement" conditions being found in the base- 
ment of the same building, a comparatively cool situation, yet with a 
relatively high degree of humidity. 

Baton Rouge., La. — The seeds were sent to Baton Rouge on February 
17, 1900. ' On June 18 the first complete set was received in return. 
The second set remained until Octol^er 22, making the time of absence 
121 days for the first and 247 for the second set. "Trade conditions" 
at Baton Rouge were furnished by keeping the seeds throughout the 
entire time of the experiment on shelves in a grocery store, the doors 
of which were not closed except at night. These conditions were thus 
identical with those to which seeds are subjected when placed on sale 
in small stores. The "dry room" was a class room on the second floor 
in one of the college buildings. A storeroom in the basement of a 
private residence, having two sides walled with brick, furnished 
' ' basement " conditions. 

« Presumably these were in a dry place, but further evidence showed that the pre- 
sumption was erroneous. The vapors arising while cooking was being done on the 
stove gave rise to conditions very detrimental to a prolonged life of the seeds. 
25037— No. 58—04 4 



50 THE VITALITY AND GEKMINATION OF SEEDB. 

W(i(/onet\ hid. T. — The seeds were sent to Wa<^oner on February 
17, 1900. The lirst series was received in return on June 2o, after 126 
days; the second set was returned after 238 daj^s, on October 13, I'JOO. 
The sets for "trade conditions " were kept in a drug- store, on a counter 
near an open door. The "dry room" was a sleeping- room on the iirst 
floor of the same building, while "basement" conditions were supplied 
by keeping the seeds in a large depository vault in a bank. 

Darhmn, W. II. — The two sets of seeds were sent to Durham on 
February 17, 1900, and were returned on July 14 and October 20, after 
117 and 231 days, respectively. The seeds under "trade conditions" 
were kept over a door at the entrance of one of the college buildings. 
The door opened into a hall, which led into office rooms, the chemical 
laboratory, and the basement. An office room on the first floor of the 
same building- supplied "dry room" conditions. The seeds were 
located well toward the top of the room, which was heated with steam 
and remained quite dry at all times. The "])asement" conditions 
were found in a storage room in one corner of the basement of the 
same building. 

Ann ArJ}(>i\ Midi. — The set of samples placed under "trade condi- 
tions" was kept in the botanical laboratory, being moved about from 
time to time in order to supply the necessary variations to an herbarium 
room, to an open window, and to an attic. From February IS, 1900, 
until May 12, 1900, the set of seeds under " dry room" conditions was 
stored in a furnace room. The seeds were only a few feet from the 
furnace and were always quite dry and warm: The maximum tem- 
perature recorded was 43 - C, with a mean of 38^ during cold weather, 
and of 30^ C. during milder weather. On May 12 this set of seeds 
was transferred to the her})arium room on the fourth floor of the 
botanical laboratory, where they remained until vitality tests were 
made. " Basement" conditions were found in a fruit cellar, having 
two outside walls and a temperature fluctuating ])etween 10'^ and Vo^ C. 

These packages and bottles were all securely packed in new cedar 
l)oxes from which they were not removed until after their return to the 
laboratory. 

RESULTS OF THE GERMINATION TESTS. 

After receipt of the seeds, germination tests were made as rapidly 
as possible, the results of which are given in the tabulations which 
follow. Likewise, in each case is shown the vitality of the control 
sample. Furthermore, a sunnnaiy of each table is given, showing the 
average percentages of germination of the seed from the various 
places for the first and second tests, respectively. From these results 
the average percentage of loss in vitality has ])cen calculated, reckoning 
the germination of the control sanq^le as a standard. It is thus a very 
simple matter to compare the relative merits of the ditierent methods 
of storing and the role they play in pronioting the longevity of seeds. 



COMPARISON OF METHODS OF STORING AND SHIITINO. 



51 



Taisle XII. — Percentage of (jermlnaiiun of beans subjected to various conditions of storage 

ill, different localities. 



[tiermination of control sample: First test, ' 


)8.7 per cent; second test 


98.7 i>er cent.] 






Order of 
tests. 


Num- 
ber of 
days in 
storage. 




Percentage of 


germination. 




I'lace of storage. 


Trade con- 
ditions. 


Dry rooms. 


Basements. 




Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Lake City, Fla 

Do 


Fir.st 

Second . 

First.... 
Second . 

First 

Second . 

First.... 
Second . 

First 

Second . 


lLi9 
23-1 

102 
275 

140 

202 

121 
247 

131 


98 
84 

98 
5G 

58 


96 
60 

100 
90 

96 

82 

100 

78 

98 
100 


98 
98 

97. 5 
98 

96 
90 

100 
96 

100 
98 

90 
100 

100 
. 96 

84 
100 


98 
90 

100 
94 

82 


92 

28 


98 
98 

100 
98 

100 
98 

100 
100 


86 


97. 9 
0(i 



54 



98 
100 


Auliurn, Ala 

Do 


97. 5 
100 


Mobile, Ala 


100 


Do 


98 




98 


Do 


98 






Do 










Wagoner, Ind. T 


First.... 
Second . 

First.... 
Second . 

First... 


120 

238 

147 
251 


98 

100 
98 

98 
100 


100 
100 

98 


100 

84 

100 


98 


Do 


98 


Durham, N. H 


100 


Do 


90 92 


98 




84 
91. 5 


98 
92 


92 


Do 


Second . 




100 




[First.... 
jsecond . 

[First.... 
jSecond . 






Average percentage of ger- 
mination. 


128 
251 


93 
69.50 


96.44 
97 


95.43 
69.33 


97. 14 
97. 36 


60. 99 
55. 66 


97. (!4 

98. 86 


Average percentage of gain 
or loss in vitality. 


128 
251 


5.78 
29. 59 


2.29 
1.72 


3.31 
29. 76 


1.58 
1.36 


32.13 
43.61 


1.06 
-t-0.10 



The beans at Mobile were seriously affected under all conditions 
except when put up in bottles and thus protected from the moist 
atmosphere. Those kept in bottles under "trade conditions" deteri- 
orated to 90 per cent, but the result of the first test of the same series 
indicates that some moisture passed through the cork and that the 
seeds were injured in that way. 

At Baton Rouge the beans retained their vitality somewhat better; 
but even here all those from the envelopes were practically worthless 
after 247 days, for beans that germinate only 60 per cent are of no 
value for planting. 

The "trade conditions" at Auburn, Ala., and Durham, N. H., were 
also very unfavorable to the prolonged vitality of the beans. At 
Wagoner, Ind. T., San Juan, P. R., and Lake City, Fla., there was a 
marked deterioration, yet not sufficiently great during the time g^ivcn 
to render them worthless for planting. However, it is quite evident 
that beans subjected to such conditions of storage would not be fit for 
planting the second season. 

A summary of the table shows that the vitality of the beans when 
kept in bottles and subjected to either of the three conditions was not 
interfered with. The averages .show a variation of less than 2 per 
cent. With those kept in paper packages the results were quite dif- 
ferent, the advantage being slightly in favor of the "trade condi- 
tions." The loss in vitality was 29.59, 29.76, and 43.61 per cent, 
respectively, for "trade conditions," "dry rooms," and "basements." 



r^9 



THE VITALITY AND GERMINATION OF SEEDS. 



Tablk XIII. — FcrcentcKje of gi'i-miiKiHon of peas subjected t.v various comlitioiis of storage 

in different localities. 

[(icrminiUicin of coiitrul sample: First test, 95.3 per cent; second test, 95. 7 per cent.] 





Ortler of 
tests. 


Num- 
ber of 
days in 
storage. 




Percentage of germin 


ition. 




Place of storage. 


Trade condi- 
tions. 


Dry rooms. 


Basements. 


. 


Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 




First 

Second . 

First.... 
Second . 

First 

Second . 

First.... 
Second . 

First.... 
Second . 

First. . . . 
Second . 

First.... 
Second . 

First 


129 
234 

102 
275 

140 

262 

121 
217 

131 

126 

238 

147 
251 


9() 

86 

93.3 
97.9 

69. 2 
44 

94 
80 

94 
98 

98 
80 

98 
94 

90 
98 


97.9 

98 

94 

94 

92 
100 

92 

88 

100 

98 

90 
92 

94 

98 

94 
94 


94 
92 

87.8 
90 

88 
42 

94 
70 


94 
92 

97.8 
96 

96 
96 

90 
98 


90 
6 

93.9 

86 

10.2 

90 



98 


Do 


98 


Auburn, Ala 

Do 


94 

98 




98 


Do 


98 




98 


Do 


98 






Do 












96 

100 
94.7 

94 
94 


92 
96 

98 
96 

72 
92 


90 

88 

94 

98 

96 
86 


88 


Do 


92 


Durham, N. H 


98 


Do 


90 




94 


Do 


Second . 

f First.... 
(Second . 

1 First 

{second . 




100 






Average jiercentage of ger- 
mination. 


128 
251 


91.56 

84.74 


94.24 
96.25 


93.4 
80. 45 


91.41 
95.14 


81.44 
60.66 


96.43 
96.28 


Average percentage of gain 
or loss in vitality. 


128 
251 


3.92 
11.45 


1.12 
0.47 


1.99 
15. 94 


4.08 
0.58 


14. 55 
36. 62 


+0.U 
-1-0.60 



The peas retained their vitality much better than the beans. How- 
ever, the greatest loss in both peas and beans was in the envelopes at 
Mobile and Baton Rouge. Some of the samples from the envelopes 
germinated fully as well or even better than the control, but the gen- 
eral averages of the second tests for all of the localities show a loss of 
11.45 per cent in ''trade conditions," 15.91 per cent in "dry rooms," 
and 36.63 per cent in "basements." The beans under identical condi- 
tions lost 29.59, 29.76, and 13.61 per cent, respectively. 

The seeds kept in bottles deviated but very little from the standard 
of the control. 



COMPAJIISON OF METHODS OF STORING ATSTB SHIPPING. 



58 



Table XIV. — Prrcrnfngr of germmatinn of cabhage aubjcrted to various cDinlilioiis of 

storage in different londities. 

[Germination of control sample: First test, 92.7 per cent; second test, 92.4 per cent.] 



Place of storage. 



Lake City, Fla 

Do 

Anburn, Ala 

Do 

Mobile, Ala 

Do 

Baton Rouge, La 

Do 

San Juan, P. R 

Do 

Wagoner, Ind. T 

Do 

Durham, N. H 

Do 

Ann Arbor, Mich 

Do 

Average percentage of ger- 
mination. 

Average percentage of gain 
or loss in vitality. 



Order of 

tests. 



First.... 
Second . 

First.... 
Second . 

First.... 
Second . 

First.... 
Second . 

First.... 
Second , 

Finst..., 
Second . 

First..., 
Second 

First..., 
Second , 



First... 
Second 

JFirst... 
[Second 



Num- 
ber of 
days in 
storage. 



129 
234 

102 
275 

140 
262 

121 
247 



126 

238 

147 
251 



128 
251 



128 

251 



Percentage of germination. 



Trade condi- 
tions. 



Envel- 



89.5 
63.5 

91 
61.5 

64.5 
17 

88.5 
25.5 

82 
76.2 

83.5 
70.5 

93 
12 

96 
91 



86 
52. 15 



7.23 
43.56 



Bottles. 



92.5 

89.5 

90.5 
90 

93.5 

87. 5 

93 
90.5 

95. 5 

89 

93 
91.5 

97.5 
92.6 

92 
94 



93.47 

90. 56 



-1-0.83 
1.94 



Dry rooms. 



Envel- 
opes. 



89.5 
81.5 

89.5 
90 



90.5 
11.5 



94 



86.43 
61.5 



6.77 
33. 44 



Bottles. 



95.5 
92.5 

96 
95.5 

90.5 

82 



92 

89.93 



0.86 
2.67 



Basements. 



Envel- 
opes. 



86.5 
14. 5 

92 
60 

5.8.5 



79. 5 
0.5 



Bottles. 



88.5 
76.5 

95.5 
92. 5 

89. 5 
76 



84.29 
53.33 



9.07 
42. 29 



90. 6 
91. 5 

91 

85. 5 

92. 5 
94 

94 
90. 5 



97. 5 

89 

94.5 
96. 5 
94.5 
95. 5 



93. 5 
92. 21 



-fO.86 
0.22 



Table XIV shows that the cabbage, like the peas, was injured to a 
less deg-ree at Mobile and Baton Rouge than the beans, but even the 
cabbage seed kept in the paper packages in these cities were all but 
killed. The average degree of injurj^ however, was greater in the 
cabbage than in the beans. In a majority of cases there was more or 
less deterioration in the case of this seed kept in the envelopes. Aside 
from those alread}" mentioned, the trade conditions at Durham, N. H., 
and the basement at Lake City, Fla., should bo expressly noted. 

The seeds kept in the bottles deviated but little from the control, 
while those kept in paper packages germinated only 62.15, 61.50, 
and 53.33 per cent for the trade conditions, dry room, and basement — 
equivalent to a loss in vitality of 43.56, 33.44, and 42.29 per cent, 
respectively. 



54 



THE VITALITY AND OERMINATION OF SEEDS. 



Tahle XV. — Prrccnhujc <•/ i/rniiination of radish subjected to rorloiis rondif ions of storage 

in different localities. 

[Germination of control sam7)le: First test, S3.C per cent; second test, 7S.8 per cent.] 





Order of 
tests. 


Num- 
ber of 
days in 
storage. 




Percentage o 


germin 


xtion. 




Place ol" storage. 


Trade condi- 
tions. 


Dry rooms. 


Basements. 




Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Lake City, Fla . . . 


First.... 
Second . 

First.... 
Second . 

First 

Second . 

First.... 
Second . 

First.... 
Second . 

First 

Second . 

First.... 
Second . 

First 


129 
234 

102 

27ri 

140 
202 

121 
247 

131 

120 

238 

147 
251 


79 
58. 5 

7-5. 5 
03 

58. 5 
51 

77. 5 
55.5 

04 
62 

77.5 
00. 5 

80.0 
69.5 

82.5 
77.5 


78. 5 
04 

85 
72. 5 

8] 
71.5 

85. 5 
09. 5 

81.5 
73.5 

80.5 
75.5 

75.5 
81.5 

85 
80. 5 


84. 5 
07.5 

85. 5 
00 

.50. 5 

49 

73.5 
49. 5 


75 
71.5 

80.5 
73. 5 

81 
70 

78. 5 
74.5 


66 
48. 5 

86. 5 
00. 5 

61.5 
51.5 


83 


Do 


67 


Aiibnrn, Ala 


8,5.5 


Do 


70. 5 


Mobile, Ala 


76 


Do ... ... 


72 




78 5 


Do 




San .Tnan, P. R 




Do 












79 

76.5 
74.5 

82. 5 
79.5 


84 

77 

85 

85 

79.5 
.57. 5 


80. 5 
63 

81 
0)8 
78 
62. 5 


86.5 


Do 


70 5 




74 


Do 


79 


Ann Arbor, Midi 


82 9 


Do 


Second . 

[First.... 
jsecond . 

P^ir.st.... 
Second . 




78. 5 


Average i)erccntage of ger- 
mination. 


12S 
251 


74.39 
60.94 


81. 50 
73. 50 


70. SO 
64. 33 


80. 5 
72.71 


75. 5 
59 


80. 91 
74.07 


Average percentage of loss 
in vitality. 


128 
251 


11. 02 
22.67 


2.44 
6.65 


8.07 
18.37 


3.71 
7.73 


9.67 
25. 13 


3.22 
6 



The results of the tests of the radish seed are very similar to those 
of the (•al)))ao-e; the latter, however, showed a g-reater loss in vitality. 
As shown l)y the second tests, the average percentages of deterioration 
of the cal)l)age seed which was kept in the envelopes were as follows: 
Trade conditions, 43.56 per cent; dry room, 33.44 per cent; basement, 
42.29 per cent, while the loss in vitality of the radish was only 22.67, 
18.37, and 25.13 per cent, respectively. 



COMPARISON OF METHODS OF STORING AND SHIPPING. 55 

Taumo XVI. — J'rrrnit(t(jr (if f/i'niil)uitlon of carrot subjcctid la vdj'invs conditions of Ktor(i(/e 

in different localitiest. 

[Germination of control sample: First test, S3.3 per cent; second test, S'i per cent.] 





Order of 

tests. 


Num- 
ber of 
days in 
storage. 


Percentage of germination. 


Place of storage. 


Trade condi- 
tions. 


Dry rooms. 


Basements. 




Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 




First 

Second . 

First.... 
Second . 

First 

Second . 

First.... 
Second . 

First.... 
Second . 


129 
234 

102 

275 

140 
2G2 

121 
247 

131 


76.5 
43.5 

84.5 
30 

59 

8.5 

74.3 
25 

71.5 
48.5 

81.5 
49 

78 
2 

76 
86 


83 
80.5 

82 
76.5 

87.5 
86 

82.3 
72.6 

82.5 
86.5 

82 
81. 5 

82. 5 
85. 5 

79 

78 


78 
67.5 

83 
72.5 . 

51. 5 
.5 

75.1 
16.5 


78.5 
78.5 

86 

76. 5 

83.5 
69 

86.8 
52. 5 


73 
3 

86.5 
47. 5 

20.5 

57.3 





Do 


SI. 5 




Do 




Mobile, Ala... 


87 


Do 








Do 


39 


Sixn .Tnan, P. R 




Do 












First.... 
Second . 

First.... 
Second . 

First 


12C 

23S 

147 
251 


77.5 

84 
87. 5 

S3 
78.5 


81 
81 

85.5 
85.5 

75. 5 
80 


77.5 
45.5 

83. 5 
72 

78 


87 5 


Do 

Durham, N. 11 

Do 

Ann Arbor, Mich 


84 

82. 5 
87. 5 
.1^3 r-i 


Do 






58 5 1 71 




jFirst.... 
[Second . 

jFirst.... 
jsecond . 






Average percentage of ger- 
mination. 


128 
251 


75.16 
37.31 


82.6 
80.87 


76. 01 
53. 83 


82.4 
74.71 


68.04 
37. 75 


83.83 
75.21 


Average percentage of gain 
or loss in vitality. 


128 
251 


9.72 
54.5 


0.84 
1.38 


8.75 
34.35 


1.08 
8.89 


18. 32 -1-0. 63 
53. 96 9. 5 



Talile XVI shows results veiy similar to those of Table XV, except 
that the carrot was affected slightly more than the cabbage. There 
was also a greater falling off in the case of the seeds kept in the bottles 
in diy rooms and ))asements. The reason for this is not very clear. 
Apparently it was due to some local conditions, inasmuch as it was 
confined chiefly to the Ijottles kept at Mobile and Baton Rouge. The 
average results of the germination tests of the seeds kept in packages 
are quite low for the carrots. Seed from trade conditions germinated 
37.31 per cent, from basements 37.67 per cent, and from dry rooms 
63,83 per cent, with a loss in vitalit}" of 54.5, S-i.OO, and 34.36 per 
cent, respectively. Under similar conditions the cabbage lost in vital 
ity 43.56, 42.28, and 33.45 per cent, respectively. 



56 



THE VITALITY AND OKRMINATION OF SEEDS. 



Table XyU.—rermitaye of grrminaiion of "A" Rweet corn mhjecied to various condi- 
tions of storage in different localities. 

[Germination of control sample: First test, 92.7 per cent; second test, 92.4 per cent.] 





Order of 

tests. 


Num- 
ber of 
days in 
storage. 


Percentage of germination. 


Place of storage. 


Trade condi- 
tions. 


Dry rooms. 


Basements. 




Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 




First 

Second . 

First 

Second . 

First.... 
Second . 

Fir.st.... 
Second . 

First 


129 
234 

102 

275 

140 

2i;2 

121 
247 

131 


94 
92 

96 

88 

SO 
20 

90 

88 

90 
92 

90 
90 

100 
90 

100 

98 


96 
100 

98 
98 

100 
90 

94 
90 

94 

94 

98 
90 

92 
96 

SO 
98 


94 
96 

94 
94 

80 
20 

9f; 

88 


92 
90 

98 
90 

90 
100 

88 
90 


88 
54. 5 

100 

80 

94.1 

86 
14 


98 


j)o 


100 


Auburn, Ala 

Do 

Mobile, Ala 

Do 


92 
100 

96 
96 




100 


Do 

San Jnan, P. R 

Do 


100 












First.... 
St'cond . 


120 

238 

147 
261 


94 

95. 9 
90 

94 
100 


90 
90 

90 
90 

89 
96 


90 
92 

TOO 
100 

100 
92 


96 


Do 


94 


Durham N H 


First.... 
Second . 

First 


96 


Do 


98 




96 


Do 


Second . 




98 




[First.... 
{second . 

(First.... 
[Second . 






Average percentage of ger- 
mination. 


12.S 
251 


94. 75 
83 


94. 75 
96. 75 


92.56 
83.33 


94.14 
94.86 


94.87 
72.08 


96.29 

98 


Average percentage of gain 
or loss in vitality. 


128 
251 


+2. 21 
10.11 


+2. 21 
-f4.71 


0.15 
9.81 


-t-O.Ol 
+2.66 


+2.34 
22 


+3.87 
+6.06 



Table XVIII. — Perccntnge of germination of "J?" siveet corn sidijecfrd to various condi 
lions of storage in different localities. 

[Germination of control sample: First test, 89.3 per cent; second test, 88.5 per cent.] 





Order of 
tests. 


Num- 
ber of 
days in 
storage. 


Percentage of germination. 


Place of storage. 


Trade condi- 
tions. 


Dry rooms. 


Basements. 




Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Lake City, Fla 


First 

Second . 

First.... 
Second . 

First.... 
Second . 

First 

Second . 

First 

Second . 


129 
234 

102 
275 

140 

202 

121 
247 

131 


86 
77.] 

88 
62 

48 
12 

SO 
54. 2 

72 

78 

70 

78 

89. 3 
82 

92 
80 


60 
2 

92 
50 

81.2 
52 

82 
30 

72 
71.7 

82 
70 

69. 5 
91.8 

88 
92 


90 
04 

80 
82 

00 
10 

81 
60 


38 


86 
38 

87. 5 
54 

94 

40 


76 
30 

SO 

82 

75 

01 
4.5 


46 


Do 







84 


Do 


89. 6 


Mobile, Ala 


86 


Do 


70 




88 


Do 


01.2 






Do 












First.... 
Second . 

First.... 
Second . 

First 


120 
238 

147 
251 


90 

84. 2 

81 

88 
86 


88 
88 

S3. 6 

88 

48 
22 


84 

88 

80 
76 

S8 
82 


84 


Do 


70 


Durham, N. H 


SO 


Do 


88 




96 


Do 






88 




(First.... 
[Second . 

fFir.st.... 
{second . 






Average percentage of ger- 
mination. 


128 
251 


78.16 
65. 41 


78. 31 
59.70 


83. 17 
66.33 


75. 01 

48 


79 
60.41 


80. 55 
68.40 


Average percentage of loss 
in vitality. 


128 
251 


12. 47 

26. 09 


12. 31 
32. 55 


6.87 
25. 06 


16 
45. 76 


11.54 

31.7) 


9.80 
22. 71 



COMPART^iOlSr OF METHODS OF STOKING AND SHTPPTN(}. 57 

Tables XVII and XVIll have been considered together, since both 
have to do with the same variet}^ of sweet corn. The difference in the 
(juality of these two samples was quite marked when the seed was 
received. Germination tests were made January 30, 1900, and showed 
94 per cent for the "A" and 88 per cent for the "B" corn. In 
November, 1900, samples of seed from the same original packages 
were tested, giving a germination of 92.4 per cent and 88.5 per cent 
for the " A '' and " B " samples, respectively, as shown in the controls 
of the above tal)les. Thus, when two grades of corn are subjected to 
favorable conditions of storage, both are well preserved; but when 
subjected to unfavorable conditions, the one of poorer quality is much 
more susceptible to injury. The "A" sample which was stored in 
envelopes in trade conditions lost 10.11 per cent, as compared with 
20.9 per cent for the "B" sample. The "A" sample which was 
stored in dr}^ rooms lost only 9.81 per cent, while the "B" sample 
lost 2.5.00 per cent. In basements, the "A" sample lost 23 per cent 
and the " B" sample 31.74 per cent. In both samples the corn in the 
packages stored in the basement at Mobile was so badly molded at the 
time the second tests were made that they have lieen omitted from the 
table. 

The most interesting feature in comparing the results of these two 
samples is found in the seed which was stored in the bottles. The 
average results of the "A" samples show a much higher percentage 
of germination for those from the bottles than the control, while the 
averages for the " B" sample were nuich lower than the correspond- 
ing controls. The average germination of the "B" sample from the 
bottles was 59.7 per cent for the trade conditions, 48 per cent for dry 
rooms, and 68.4 per cent for basements, or a loss in vitality of 32.55, 
45.76, and 22.71 per cent, respectively. This difference was due to 
two causes, first, a difference in the quality of the seed at the begin- 
ning of the experiment, and, secondly, the larger amount of water in 
the second sample, "B." The greater quantity of water present in 
the seed gave rise to a more humid atmosphere after the seeds were 
put into the bottles, especiall}' when sul^jocted to higher temperatures 
than those in which the seeds had been previously stored. This is an 
important factor always to be borne in mind when seeds are put up in 
closed receptacles; they must be well dried if vitality is to be preserved. 



58 THE VITALITY AND TERMINATION OE SEEDS. 

Taiu.r XIX. — Perccntagr of germinatloi) of Irfliire .vilijrctrd lo vdrU/UK (■(ni)Iillniit< of 
Rhirage in diflWmt localiticft. 

[termination of control sample: First test, Sl.fi jtcr cent: second test, 92.3 percent.] 





Order of 

tests. 


Num- 
ber of 
days in 
.storage. 




I'ercentage o 


germ in 


ation. 




Place of storage. 


Trade 
conditions. 


Dry rooms. 


Basements. 




Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Lake City, Fla 


First 

Second . 

First.... 
Second . 

First 

Second . 

Fir.st 


129 
234 

102 

275 

140 
2G2 

121 

247 

131 


87 

85 

80. 5 
85 

(v:, 

20 

82.5 
84.5 

79 
83.5 

78 

82 

82.5 
88. 5 

82 
92.5 


84 
92 

85.5 
90. 5 

78 
88. 5 

81.5 
93.5 

87. 5 
89 

76 
92. 5 

80.25 
93 

68. 5 
90 


81 
92.5 

88. 5 
90.5 

.58 
31 

79 
74.5 


76. 5 
90 

.84. 5 
91 

87. 5 
90.5 

78. 5 
87. 5 


68 
43. 5 

.84. 5 
83. 5 

1.5 
70. 5 


77 


Do 


95. 5 




88. 5 


Do 


90 




S3 


Do 


91. 5 




76 


Do 


92. 5 




First.... 




Do ' 









Wagoner Ind . T 


First.... 
Secoml . 

First 


126 

23S 

147 
2.'S1 


80 

83. 25 
92 

84.5 

89. 5 


82 
94 

77.5 
93 

81.5 
90.5 


81 
87.5 

80 
90. 5 

78. 5 
88 


70. 5 


Do 


89 


Durham, N. H 




Do 


90. 5 




First 


72 


1)0 . 


Second . 

jFirst.... 
(Second . 

JFirst.... 
[Second . 




91.5 






Average percentage of ger- 
mination. 


128 
251 


80.06 
77.75 


80. 15 
91.12 


79. 18 
78.33 


81.14 
90.93 


66. 28 
65. .58 


78.31 
90.78 


Average percentage of loss 
in vitality. 


128 
251 


1.89 

1.5.76 


1.77 
1.29 


2.97 
15. 14 


. 56 
1.49 


18.78 
28. 95 


4.03 
1. 05 



The lettuce has shown no vei\y marked deviation from the controls, 
save the seeds from the packages kept at Mobile, and those which were 
stored in l)asements in envelopes at Baton Rouge and Lake City. 
The average results of the second series of tests show a similar losss in 
vi tality of all of the seeds from the envelopes. The samples of seed from 
the bottles germinated practically as well as the controls. The results 
of the first series of tests are not entirely satisfactory, none of the 
tests having gone to standard. The low germination of the lettuce in 
this series was due to inability to properly control the temperature in 
the germinating pans. The proper temperature for the successful 
germination of lettuce seed is 20'^ C, while in this lirst series the ger- 
mination tests were unavoidalily made at 26 " to 27.5'' C. Neverthe- 
less, this seeming objection is of little consequence, since all of the 
results are directly comparable with the control. 



COMPARISON OF METHODS OF STORTNC} AND SnTlMM>f(l. 59 



Tahi.e XX. — Pcrcnttagr of germination of onion Hubjected lo rariouft ro)i(Iilions <if slor(i(/(' 

■in different localities. 
[(Tomiinalinn of onntrnl sample: First test, 95.8 per cent; second test, 97 per cent.] 



Place of storage. 



Lake City, Fla. 
Do 

Auburn, Ala ... 
Do 

Mobile, Ala 

Do 



Baton Rouge, La. 
Do.... 



San Juan, P. R. 
Do 



Wagoner, Ind. T. 
Do 



Durhain, N. H 
Do 



Aun Arl>or, Mich 
Do 



Average percentage of ger- 
mination. 

Average percentage of gain 
or loss in vitality. 



Order of 

tests. 



Num- 
ber of 
days in 
storage. 



Fir.st.... 
Second . 

First 

Second . 

First.... 
Second . 

First 

Second . 

First.... 
Second . 

First.... 
Second . 

First 

Second . 

First 

Second . 



[First 

ISecond . 

I First.... 
[Second . 



129 
234 

102 
275 

140 
262 

121 

247 



12f) 
238 

147 
251 



128 
251 



128 
251 



Percentage of germination. 



Trade condi- 
tions. 



Envel- 
opes. 



95 
16.5 

96 
12 

7 


90 
0.5 

84.5 
50 

93.5 
24.6 

96. 5 


95 
97.5 



Bottles. 



82. 19 
25. 12 



14. 20 
74.11 



95 
95. 5 

96. 5 
96 

94.5 
94.5 

93 
97.5 

98 
96.5 

97.5 
95 

9G 
97.5 

96 

97.5 



Dry rooms. 



Envel- 
opes. 



95. 5 

79 

96 
96 

11.5 


94 




95. 5 



95. 81 
96. 25 



-fO.Ol 
1.20 



94. 5 
96 

99. 5 
95 



S3. 79 
61 



12. 53 
37.12 



Bottles. 



95 
9(! 

98. 5 
98 

91"). 5 
96. 5 



Basements. 



Envel- 
opes. 



97 
97.5 

96 
97 

97 
96. 5 



96. 21 
92.36 



-f- 0.43 
4.80 



80 


97 
23.5 

75. 5 
«0 



81.36 
33. 08 



15. 07 
65. 90 



Bottles. 



97.5 
97.0 

97.5 
99 

99 
97.5 

96.6 
48.5 



94. 5 
97.5 

94.5 

98 



9(i. 64 
90.86 



+0.87 
6.33 



fiThis test has not been included in making up the averages inasmuch as the seeds were badly 
molded when put in test. 

The onion seeds which were stored in the envelopes were very seri- 
ously affected in many of the places. Those from the basement at Lake 
City, froni all of the conditions at Mobile, and from the dry room and 
basement at Baton Rouge were entirely killed. The seed from trade 
conditions at liaton Rouge germinated only 0.5 per cent. In man}' 
other cases the samples from the envelopes had become practical!}^ 
worthless. In only two instances was there any loss in vitality wdiere 
the seeds were stored in bottles, viz, the second tests from the dry 
rooms and basement at Baton Rouge. These two tests have lowered 
the average results quite materially. If they were not included the 
averages would be raised to 96.91 and 97.90 per cent, respectively, 
instead of 92.36 and 90.86 per cent, as given in the table. The average 
percentages of germination of the seeds from the envelopes were very 
low in the second test, and were as follows: Trade conditions, 25.12 
per cent; dry rooms, 61 per cent, and basements, 33.8 per cent. This 
represents a loss in vitality of 74.11, 37.12, and 65.9 per cent, respec- 
tively. 

Onion seed is relatively short lived, and very easily affected by 
unfavorable external conditions. For this reason onion seed should 
be handled with the greatest care if vitality is to be preserved for a 
maximum period. This may be done successfully by keeping the dry 
seed in well-corked bottles, or in any good moisture-proof ptickage. 



(•)() 



thp: vitality and oermination ok seeds. 



T.\BLE XXI. ^ — Prrrerittiijr of i/mniiuilion of pdri.fi/ ftii]>jrrir(l in varimis rnnditions of 

storage in different localities. 

[Germination of control sample: First test, 63 per cent; second test, ."is per cent.] 





Order of 
tests. 


Num- 
ber of 
days in 
storage. 


Percentage of germination. 


Place of stf)rage. 


Trade 
conditions. 


Dry rooms. 


Basements. 




Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


P^nvel- 
opes. 


Bottles. 




First.... 
Second . 

First.... 
Second . 

First.... 
Second . 

First.... 
Second . 

First 

Second . 

First 


129 

234 

102 

275 

140 
2G2 

121 
247 

131 

120 

238 

147 
251 


44. 5 
1.5 

57. 5 
2 

3 


28.5 


20 
6.5 

48.5 
7. 5 

55. 5 


53.5 
46.5 


63 

.54 

68 
20.5 

57. 5 
20. 5 

53 
34 

60.5 
.58.5 

01.5 
65 

06.5 
60. 5 

51 
45 


45 
22. 5 

60. 5 

28 
•2 


38 



.58. 5 

47 

62 

27. 5 

01 
25. 5 

44 

17 


10. 5 


00 


1 

4.5 . 



02.5 


Do 


57.6 




59.5 


Do .. 


33.5 




59 


Do 


2.5 




54 


Do 


2.5 






Do 










Wagoner, Did. T 


50. 5 

49.5 
44 

69.5 
52 


02. 5 
.59. 5 

63. 5 
60. 5 

40 

48.5 


40 
.S.5 

■19 

36. 5 

.50 
3.5 


.59 


Do 


.52. 5 


Durham, N. II 


"First.... 
Second . 

First.... 


03. 5 


Do 


60 


Ann Arbor Mich 


53 


Do 


60. 5 




[First 

Isecond . 

JFirst.... 
{Second . 






Average percentage of ger- 
mination. 


128 
251 


38. 87 
8 


60.12 
44.75 


44.43 
24.41 


55. 93 
40.80 


31.. 57 

8.08 


5S. 64 
38. 43 


Average percentage of loss 
in vitality. 


128 
2.51 


38.3 
84.91 


4.57 
1.5.60 


29. 48 
.53. 97 


11.23 
23.02 


49.89 
84.70 


6. 92 
27. 49 



T;\KLE XXII. — Percentage of germination of phlox drummondii sidrjected to variotis con- 
ditionti of storage in different localities. 

[Oermination of control sample: First test, 69 per cent; .second test, ,53.9 per cent.] 





Order of 
tests. 


Num- 
ber of 
days in 
storage. 


Percentage of germination. 


Place of storage. 


Trade condi- 
tions. 


Dry rooms. 


Basements. 




Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Envel- 
opes. 


Bottles. 


Lake <;ilv, Fla 


First 

Second . 

First 

Second . 

First.... 


129 
234 

102 
275 

140 

202 

121 

247 

131 


41.5 
2.5 

61.5 

1 

0.5 


47. 5 


23. 5 
11.5 

.50. 5 
5.5 

67 
0.5 

67 
40 


78 
.57 

72.5 
.50. 5 

55 
.51.5 

02. 5 

58 

05 
01. 5 

73. 5 
00 

71 
02. 5 

66 
64 


02 


02 
13.5 

0.5 


43. 5 



02 
25. 5 

63 
59 

74. 5 

58. 5 

.58. 5 
58. 5 


20.5 


05. 5 
1 
0. 5 

2 



77.5 


Do 


63 


Auburn, Ala 


67.5 


Do 


65 


Mobile, Ala 


.58. 5 


Do 


48 5 




First.... 
Second . 

Fir.st 

Second . 


70 5 


Do 


61.5 


San .Juan, P. R 




Do 










Wagoner, I nd. T 


First.... 
Second . 

First 

Second . 

First 


126 
238 

147 
2.51 


01 

02. 5 
33 

75. 5 
55 


70 

57 

4.5. 5 
30. 5 

69. 5 

.58. 5 


05 
9.5 

09. 5 
4.5. 5 

04. 5 
10.5 


75 


Do 


47.6 


Durham, N. 11 


71.5 


Do 


70 


Ann Arbor, Midi 




Do 


Second . 




61 




(First.... 
(Second . 

[First 

(Second . 






Average percentage of ger- 
mination. 


128 
251 


44.87 
7.62 


68.31 

58. 37 


.52. 70 
17.91 


63. 28 
49. 64 


41.07 
11. 08 


70. 35 
69.5 


Average percentage of gain 
or loss in vitality. 


128 
251 


34.97 

85. 80 


1 
-1-8.27 


28. .54 

00. 78 


8.29 
7.91 


40. 49 
79.45 


+ 2.01 
4-10.39 



COMPARISON OF METHODS OF STORING AND SHIPPING. 61 

Pansy and phlox have been considered together, since their behav- 
ior was ahnost the same. Both of the controls deteriorated to a con- 
siderable degree during the 123 days which elapsed between the time 
of the lirst and the second test, pansy losing 15.87 per cent and phlox 
21. SS per cent. In both cases the mean loss in vitality of the seeds in 
the envelopes was very great. The results of the second tests show a 
loss of 81.91 per cent for pansy, and 85.86 per cent for phlox where 
stored under trade conditions. In dry rooms there was a mean loss 
of 53.57 per cent for pansy and 66.78 per cent for phlox, and in base- 
ments a loss of 81.76 per cent for the pansy and 79.15 per cent for the 
phlox. These results are obtained by considering the second test of 
the control as a standard, the depreciation of the control being dis- 
regarded. Some samples were dead and many more were of no eco- 
nomic value. It is especially interesting to note how quickly the seeds 
died at Mobile, Ala., there being only a few germinable seeds at the 
end of 110 days. 

The behavior of the seeds in the bottles was more or less variable. 
Some of the pansy seeds showed a higher vitality than the control, but 
the averages were somewhat lower, the mean loss ranging from 15.60 
per cent under trade conditions to 27.19 per cent in basements, while 
with the phlox the means for trade conditions and for basements were 
higher than the control by 8.27 and 10.39 per cent, respectively. 



Table XXIII. — Percentages of germination of tomato subjected to various conditions of 
storage in different localities. 

[Germination of control sample: First test, 95.6 per cent; second test, 97.5 per cent.] 



Place of storage. 



Lake City, Fla . 
Do 

Auburn, Ala ... 
Do 

Mobile, Ala 

Do 



Baton Rouge, La. 
Do 



San Juan, P. R. 
Do 



Wagoner, Ind. T. 
Do 



Durham, N. H . 
Do 



Ann Arbor, Mich 
Do , 



Average percentage of ger- 
mination. 

Average percentage of loss 
in vitality. 



Order of 
tests. 



First..., 
Second , 

First..., 
Second , 

First 

Second 

First..., 
Second , 

First..., 
Second , 

First..., 
Second , 

First..., 
Second , 

First..., 
Second 

First... 
Second 

[First... 
[Second 



Num- 
ber of 
days in 
storage. 



129 
234 

102 
275 

140 
262 

121 

247 



Percentage of germination. 



Trade condi- 
tions. 



Envel- 
opes. 



126 
147 

147 
251 



128 
251 



128 
251 



94 
94 

95 
94 

90 
79.6 

91.5 
96 

94 
96.5 

96.5 
94 

94.5 

87 

89 
98.5 



93.06 
92.44 



2. 56 
6.20 



Bottles, 



94.5 
98.5 

94.5 
97. 6 

95 
96. 5 

94.5 
94 5 

97 
98 

95 

98 

94 

98 



94.81 
97.31 



0.72 
0.20 



Dry rooms. 



Envel- 
opes. 



94 
94 

93.5 
97 

91.5 

87 

91 
93 



1.57 
3.29 



Bottles. 



96. 5 

97.5 

97.5 
94.5 

96.5 
95.5 

96 

98 



96. 6 
97.5 

94 
99 

91.5 
97.5 



95. 21 
97.07 



0.30 
0.44 



Envel- 
opes. 



88.6 
77 

96 

98 

64. 5 
19.6 

83. 6 
39.6 



98.6 
98.5 

97.6 
97.6 

89 
95 



88.21 
84.25 



7.64 
13.63 



Bottles. 



94 
97.5 

94.5 
96.5 

93.5 

98 

95 
96 



96 
93.5 

96.5 
97 

92.5 
98 



94.57 
97.21 



0.98 
0.30 



G2 



THE VITALITY AND GERMINATION OF SEEDS. 



The tomato .scud, as .shown in Tables V and XXV, was the most 
resistant to the unfavoraV^le conditions of storage. The .seed in the 
bottles was not injured at an}^ of the places. The lowest germination 
was 91.5 per cent from the seed kept in a dry room at Ann Arl)or, 
Mich. The seed in the envelopes gave a much wider variation, falling 
quite low in some of the samples which were stored in the basements. 
The average losses in vitality for the entire series of the second set of 
seeds which were kept in envelopes were as follows: Trade conditions, 
5.20 per cent; dry rooms, 3.29 per cent; basements, 13.03 per cent. 
The average percentage of germination of the seed which was kept in 
the ))ottles ditl'ered from the control less than one-half of 1 per cent. 

Taisle XXIV. — Fcrceyilitge of (jcrtnination of watermelon subjecled to vuriuus condltmis 
of storage in differeyit localities. 

[Uoruiinatioii of control .sampk': Fir.st test, 95.5 per cent; second test, "JS) per cent.] 



Place of storage. 



Lake City, Fla . 

Do 

Auburn, Ala ... 

Do 

Mobile Alii 

Do 



Baton Rohrc, La. 
Do 



San Juan, P. R 
Do 



Wagoner, Ind. T. 
Do 



Durliaru, N. H 
Do 



Ann Arbor, Mich . 
Do 



Average percentage of ger- 
mination. 

Average peccntage of loss 
in vitality. 



Order of 

tests. 



First... 
Second 

First..., 
Second , 

First..., 
Second , 

First..., 
Second , 

First... 
Second , 

First..., 
Second , 

First..., 
Second , 

First 

Second , 

(First..., 
Isecond . 

[First.... 
Isecond . 



Num- 
ber of 
days in 
storage. 



129 
234 

102 
275 

140 
262 

121 

247 



126 
238 

147 

251 



128 
251 



128 
251 



Percentage of germination. 



Trade condi- 
tions. 



Envel- 
opes. 



100 
92 

96 

88 

98 
94 

98 
82 

100 
96 



Bottles. 



97.75 
86.75 



0.56 
12. 37 



98 
96. 2 

94 
100 

98 
96 

98 
98 

100 
100 

98 
98 

98 
96 

100 
100 



98 
98.02 



0.31 
0.99 



Dry rooms. 



Envel- 



100 

98 



96.86 

88.67 



1.47 
10.44 



Bottles. 



98 
98 

98 
98 

100 
96 

100 
100 



100 
96 

98 
92 

94 
92 



98.29 
96 



Basements. 



Envel- 
opes. 



96 

88 

98 
94.1 

98 
100 



95.29 
77.70 



0.01 
3.03 



3.06 
21.52 



Bottles. 



100 
94 

100 
96 

100 
100 

98 
100 



98. 29 
97.43 



0.01 
1.59 



What has been said of the tomato seed is practically true for the 
watermelon, .save that there was a greater loss in vitality in the latter, 
when seed;j were kept in envelopes. The average percentage of ger- 
mination of the second tests was 86.75 per cent for trade conditions; 
88.67 per cent for dry rooms; and 77.7 per cent for basements, or a 
lo.ss in vitality of 12.37, 10.44 and 21.52 percent, respectively, as com- 
pared Avith the vitality of the control sample, which germinated 99 
per cent. 

An examination of the foregoing set of tables will show that in 
mo.st cases the deteriortition was comparatively slight during the first 
128 days. Yet even during this short period the losses in vitality 
were very marked in some of the more critical localities, particularly 



COMPARISON OK METHODS OF STOKTNO AND SHIIMTNG. 08 



lit Mobile. However, the j^Tcatest lo.ss, a.s shown ))y the o-eniiination 
tests, was during the 1'2'd daj^s immediately followino-. 

While seeds, like other living things, are capable of withstanding 
([uite unfavorable conditions for a considerable time without showing 
any appreciable deterioration in vitalit}^ still the forces destroying 
\itality are at work. When the turning point is once reached and can 
be detected by germination tests, the decline is more noticeable and 
death soon follows. 

The preceding tables show that the loss in vitality was very differ- 
ent in the different places. The conditions at Mo1)ile, Ala., proved to 
be the most injurious, while those at Ann Arbor, Mich., were the 
most conducive to longevity. These results, however, are given in 
anotlier part of this paper dealing with the effect of climate on the 
vitality of seeds. The results are tabulated on pages 18 and 23 and 
represented diagrammatically on page 24c, so that any further discus- 
sion at this time is unnecessary. 

Likewise each table has been summarized, giving the average per- 
centages of germination and the average percentages of the loss in 
vitality of each sample of seed for both the first and second tests. 
These averages include those of the three conditions of storage — trade 
conditions, dry rooms, and basements— in both envelopes and bottles. 

Naturally, the results of the second tests are of the greater impor- 
tance, and, in order that the results may be readily compared and more 
critically examined, they have been collected and tabulated herewith: 

Taule XXV. — Airnuje percentage of germination and average percentages of loss in 
vitality of the different kinds of seeds when kept under different conditions. 





1 

c 
o 
a 

.2 3 

^^ 

a 

a 

o 


Trade conditions. 


Dry rooms. 


Basements. 




Envelopes. 


Bottles. 


Envelopes. 


Bottles. 


Envelopes. 


Bottles. 


Kind of set'd. 


o 
a 

a 


o 


(3 
O 

a 

a 


1 

o 
1-1 


S 
a 

a 

o 


a 
o 


B 
O 

'S 

1 

o 


2 
o 


S 

a 

0) 

O 


o 


3 


a 

§ 
iJ 




97.5 
92.4 


92.44 
83 


5.20 
10.11 


97.31 
90. 75 


0.20 

+4.71 


94.33 
83.33 


3.29 
9.81 


97.07 
94.86 


0.44 
+2.66 


84.25 
73.08 


13.63 
22 


97.21 
98 


0.30 


SWL-ct com, "A" .. 


+ 6.00 


IViis 


95.7 


84.74 


11.45 


95.25 


.47 


80.45 


15.94 


95.14 


.58 


60.66 


3(;. 62 


90. 28 


+ .60 


WatcruiL'loii 


99 


' 86. 75 


12. 37 


98. 02 


.99 


88. 67 


10.44 


96 


3.03 


77.70 


21. 52 


97. 43 


1.59 


Lettuce 


92.3 


77.75 


15.70 


91. 12 


1. 29 


78.33 


15.14 


90.93 


1.49 


65.58 


28.95 


90. 78 


1.05 


Kiidisli 


78. S 


60.94 


22.67 


73.56 


6.65 


64.33 


18.37 


72. 71 


7.73 


69 


25.13 


74.07 


6 


Sweet corn, "B" .. 


88.5 


C5.41 


26.09 


59.70 


32.55 


66.33 


25.06 


48 


45.76 


60.41 


31.74 


68. 40 


22. 71 


Bean 


98.7 


69.50 


29.59 


97 


1.72 


69.33 


29.76 


97.36 


1.36 


55.66 


43. 61 


98. 86 


+ .10 


Cabbage 


92.4 


52. 15 


43.56| 90.56 


1.94 


61.50 


33.44 


89.93 


2.67 


53.33 


42.29 


92.21 


.22 


Carrot 


82 


37.31 


54.50 


80.87 


1.38 


53.83 


34.35 


74.71 


8.89 


37.75 


53. 96 


7.5.21 


9. 50 


Onion 


97 
53 


25. 12 

8 


74.11 
84.91 


90.25 
44. 75 


1.20 
15.60 


61 

24. 41 


37.12 

53.97 


92.36 

40.80 


4.80 
23.02 


38.08 
8.08 


65.90 
84.76 


90. 86 
38. 43 


C. 33 


I'ansy 


27. 49 


Phlox 


53. 9 


7.62 


85.80 


58. 37 


+8.27 


17.91 


60.78 


49.64 


7.91 


11.08 


79.45 


59. 50 


+ 10.39 


Average loss 




























in vitality . 






36. 63 




3.92 




21.19 




8.08 




42. 28 




4.51 



64 THE VITALITY AND OERMINATION (»K SEEDS. 

In comparing the average results shown in Tul)le XXV, it will be 
seen that different seeds behave very differently under practically iden- 
tical conditions. The list of seeds has been arranged according to 
their loss of vitality as represented by those kept in envelopes under 
trade conditions, as shown in the fourth column. The tomato seed 
gave a loss in vitality of 5.20 per cent, being the most resistant to the 
unfavorable climatic conditions. Phlox, on the other hand, germinated 
only 7.62 per cent, representing a loss in vitality of 85. SB per cent. 

Likewise the same seeds behave very differently under slightly 
different conditions, as will be seen by comparing the percentages of 
deterioration in the case of seeds kept in envelopes luider trade condi- 
tions, in dry rooms, and in basements. In dry rooms the order, except 
the peas, is the same as for trade conditions. The loss of vitality in 
the seeds stored in the dry rooms was uniforndy less than for those 
stored under trade conditions, excepting for the peas and beans; but 
in the series from the basements there was great irregularity. The 
loss in vitality for the most part was uniforndy greater than imder 
trade conditions or in dry rooms save in the last ffve — cabbage, carrot, 
onion, pansy, and phlox — where the loss Avas less in the case of those 
kept in the basements. This indicates that these live species of seed 
are less susceptible to the evil effects of a moist atmosphere when the 
temperature is relativelj^ low. 

The relative value of these three conditions for storing seeds in 
paper packets is best obtained l)y a comparison of the general averages. 
The average losses in vitally for the thirteen different samples of seed 
which were kept at the eight different stations were as follows: Trade 
conditions, 36.03 per cent; dry rooms, 21.10 per cent; basements, 42.28 
per cent. From these results it is quite clear that seeds put up in paper 
packages will retain their vitality nuich better if kept in dry, artificially 
heated rooms than if they are subjected to trade conditions or stored 
in basements. 

But another comparison needs yet to be made, and is the most impor- 
tant of the series, i. e., the vitality of seeds when kept in closely 
corked bottles. In the majority of cases there was but little deviati<^n 
from the control samples, and many of the samples germinated even 
better where the seeds were kept in bottles. The "A" sweet corn 
offers the best illustration of the increased germination. At the same 
time the "" B" sample of sweet corn was very much injured. Here are 
two samples of the same variety of corn behaving very differently 
when kept in bottles. This difference in vitality is directly attributed 
to the greater ([uantity of water in sample "B," showing the necessity 
of thoroughl}^ drying seeds if the}^ are to be put up in closed vessels. 
A comparison of the general averages of the bottle samples and of 
those kept in envelopes indicates that the former is far superior to the 
latter as a method for preserving the vitality of seeds. Under trade 
conditions the loss in vitality was 36.63 per cent in envelopes and 



EXPERIMENTS IN KEEPING AND SHIIM'ING. 05 

3.03 per cent in bottles; in dry rooms, '21.1d percent in envelopes unci 
8, OS per cent in bottles; in basements, 42.28 per cent in envelopes 
iind 4.51 per cent in bottles. 

The necessary precautions to be taken, if seeds are to be stored in 
bottles, are (1) a well-dried sample, preferably artificially dried seed, 
and (2) a cool place for storing-, at least a place in which the tempera- 
ture will not be higher than the temperature at which the seeds were 
orig'inall}' dried. 

If the above precautions are taken at least two beneficial results will 
follow: First, protection against moisture, which is of considerable 
importance, as many seeds are soon destroyed in that way when kept 
in paper packages. Secondl}^, vitality will be preserved for a longer 
period and consequently there will be a more vigorous germination, a 
l)etter growth of seedlings, and a greater uniformity in the resulting 
crop. 

Having thus shown that seeds retain their vitality in warm, moist 
climates much better when kept in bottles than Avhen kept in paper 
packages, the necessity of finding a more suitable method for sending 
small quantities of seed to such places at once presents itself. 

EXPERIMENTS IN KEEPING AND SHIPPING SEEDS IN • 
SPECIAL PACKAGES. 

At present the greatest disadvantages in sending out seeds in bottles 
are the inconvenience and expense involved by this method of putting 
up seeds. The increased cost of bottles, as compared with the paper 
packets now so universally emplo3'ed, the additional labor and expense 
necessary to put up the seeds, the greater cost in handling and pack- 
ing the bottles to insure against losses by breakage, and the increased 
cost of transportation, arc all matters of vital importance. Seedsmen 
claim that the existing conditions of the trade will not admit of their 
raising the price of seeds sufliciently high to justify the increased 
expense of glass containers. Although to the seedsmen the preserva- 
tion or the prolongation of vitality is an important factor, yet the 
demand is for an inexpensive and at the same time a neat and service- 
able package. 

Accordingly, duplicate samples of the following-named seeds were 
put up in special packages, one set being sent to Mobile, Ala., and the 
other kept at Ann Arbor, Mich. The seeds used for these experi- 
ments were beans, peas, cabbage, lettuce, onion, pansy, and phlox. « 

«The lettuce, onion, pansy, and phlox were from the same bulk samples of seeds 
as those used in the earlier experiments; but the beans, peas, and (^ahbage used for 
these tests were from samples received at the laboratory on February 4, 1901. How- 
ever, the latter three were from the same general stock of seed, differing from those 
used in experiments already given only in that they were stored during the interval 
in the warehouse of D. M. Ferry & Co., Detroit, Mich., instead of in the botanical 
laboratory at the university. 
25037— No. 58—04 5 



66 



thp: vitality and germination of seeds. 



All of these samples were tirst dried for ten days in an incubator main- 
tained at a temperature of from oi) to 32'- C. The amount of mois- 
ture in the samples ))efore and after dr3^ing-, as well as the moisture 
expelled during the drying process, was as follows: 

Iloisliirc test of nccih in special jxiclcages. 



Kind of seed. 



Beans 
Peas . . 
Cabbuj 
Lettiic 
Onion 
Pansy 
Plilox 



"it'dried" Moisture 
samples! remaining. 



Per cent. 
10.32 
9.70 
4. .S9 
5.33 
().<18 
4.82 
5. 82 



Per cent. 
4.90 
6.00 
3. 47 
3. 80 
4.47 
3.13 
4. 30 



Moisture 
liberated. 



Per cent. 
.5.42 
3.70 
1.42 
1.53 
•2.01 
1.69 
1.52 



These well-dried seeds were then put up in seven different kinds of 
packages : 

(1) Doul)le coin envelopes, of much the same qualit}^ as those in which 
seeds are commonly sold. 

(2) Bottles of 120 cc. capacity, closed with firm cork stoppers. ! 

(3) Bottles of 120 cc. capacity, corked and sealed with paraffin. 

(4) Tin cans having closely fitting lids, the whole being then care- 
fully dipped in paraffin. 

(6) Double coin envelopes, as for No. 1, the packets })eing then 
dipped in melted paraffin. 

(()) Double coin envelopes, the inner one paraffined, the outer envel- 
ope l)eing used simply to protect the paraffin and to facilitate ease of 
handling. 

(7) Doul)le coin envelopes, with both the inner and the outer coated 
with paraffin. 

On Fel)ruary 15, llX »1, one of each of the above preparations was sent 
to Mo])ile, Ala., and stored in a cellar approximately -lOO feet l)ack 
from the ba3^ After the lapse of 108 days, i. e., on June 3, these 
samples were received in return, at which time germination tests were 
made. 

The other complete set, retained in the botanical laboratory at Ann 
Ar])or, was subjected to a very moist atmosphere. The samples were 
kept in a damp chamber made by taking two battery jars of different 
sizes, the smaller containing the seeds being placed within the larger, 
which was lined with filter paper and then partiall}^ filled with water. 
The whole was covered with a glass plate, and the atmosphere within 
was always on the verge of saturation. 

A third and an extreme set of conditions was established b}^ keeping 
some of the paraffined packages immersed in water for twenty-seven 



EXPERIM.ENTS TN KEEPIJfG AND SHI1MMN(}. 07 

days. At the end of that time (March 14) the .seeds wei-e tested for 
germination, as were also those from the unprotected envelo]:)es in 
the moist chamber. The seeds that were kept under water in the 
paraffined packages germinated readily and normally, showing no 
deterioration in vitalit}^ ; but the seeds from the packages not paraffined, 
which were kept in the moist chamljer, had been injured to an appre- 
ciable extent, there being a marked retardation in the germination of 
all of the species of seed. The cabbage at the end of thirtj^-six hours 
had germinated only 11 per cent, as compared with 57.5 per cent for 
seed from the immersed paraffined package. The relative merits of 
the two conditions as affecting onion seed may be expressed by a 
germination of 13.5 per cent and 89 per cent, respectively, after sixty- 
one and one-half hours. Not only was there a marked retardation, 
but likewise a reduction in the final percentage of germination, with 
the single exception of the cabbage. These results can be more care- 
fully studied in Table XXVI. 

(Termination tests were made of all of the other samples on June 3, 
IDUl, the date when the seeds were returned from Mobile. At this time 
the seeds in the unprotected envelopes in the moist chamber were so 
badly moMed that no germination tests were made. The samples from 
Mobile, which were directly comparable with the above, except that 
they had been stored in a basement, were greatly injured. The beans 
had deteriorated to 88 per cent, the onion to 27 per cent, the pansy to 
8 per cent, while the phlox was dead. However, seed of the other 
species — cabbage, lettuce, and peas — gave final percentages of germi- 
nation varying but little from the control, but the slowing down in 
the rapidity of germination was sufficiently marked to show a corre- 
sponding loss in vitality. 

With the samples which were put up in bottles, tin cans, and 
paraffined packages the results were quite different from those given 
above. In no case was there any marked deviation beyond that which 
might be justly attriV)uted to ordinarj^ variation, except in the phlox 
from a tin can which had been stored in the moist chaml)er in the 
laboratory. This sample of phlox germinated only 3.5 per cent. 
Unfortunately, both the pansy and the phlox seeds used for these 
experiments were not very satisfactory. These samples were at this 
time nearly two years old and consequently of a low vitality. The 
tabulated results of the foregoing experiment follow. 



68 



THE VITALITY AND GEKMINATION OF SEEDS. 



Taulk XXVI. — MtaUtij of seeds pretferved in different kiitds of jxtckages. 



Trcatuit'iit of .'<iinii)k's. 



Control 

Ann Arbor, Mich., moist chambor: 

Envelopes 

Bottle, corked 

Bottle, paraffined 

Tin can, paraffined 

Two envelopes, outer paraffined 

Two envelopes, inner paraffined 

Two envelopes, both paraffined 

Two envelopes, both paraffined and 

immersed in water 

Mobile, Ala., basement: 

Envelopes 

Bottle, corked 

Bottle, paraffined 

Tin can, paraffined 

Two envelopes, outer paraffined 

Two envelopes, inner paraffined 

Two envelopes, both paraffined 



Dura- 
: ion of 
.•xperi- 
ment. 



Dai/s. 



27 
108 
108 
108 
108 
108 
108 



108 
108 
108 
108 
108 
108 
108 



Percentage of germination. 



Beans ^'^^' ^'^^' 
iseans. ^^^^ ^^^^ 



80.0 
98.0 
97.5 
96.0 
98.0 
98.0 
96.0 



.S8. 
98. 
98.0 
96.0 
94.0 
96. 
100. 



91.0 
91.5 
93.5 
87.0 
91.5 
94.0 
90.5 



86.0 
91.0 
90.5 
88.0 
90.5 
92. 
92. 



„.. On- p Pan- 
tuce. ions. ^'^*^- sy. 



76.5 
91.0 
90.5 
90.0 
91.5 
89.0 
86. 5 



88.0 
90.5 
92.5 
95.0 
89.0 
88.0 
89. 5 



90.0 
93.5 
95.5 
93.0 
97.0 
93.0 
95.5 



27.0 
95.5 
95.5 
96.0 
95.5 
90.0 
88.5 



88.0 
94.0 
90.0 
90.0 
92. 
88.0 
92. 



96.0 
84. 
92.0 
88.0 
92.0 
98.0 
90.0 



^^^' Phlox ^'^^'■" 
sy. ^liox. j^ggg 



25.0 
36.0 
39.5 
35.0 
33.5 
24.0 
23.0 



8.0 
34.5 
34.5 
26.0 
29.5 
33.0 
25. 5 



0.0 
31.0 
39.0 

3.5 
27.5 
47.0 
38.5 



0.0 
32. 5 
44.5 
23.0 
34.0 
38.0 
33.5 



77.34 

64.35 

76.43 
77.93 
70.63 
75.85 
76.14 
74.57 



56.14 

75.14 
78.21 
73.14 
74.73 
76.43 
74.14 



Subsequent experiments were made, using envelopes of different 
qualities, as well as varying the treatment of the packages. Samples 
of cabbage, lettuce, and onion seed were put up as follows: 

(a) Tlie regular seedsmen's envelope, made of a heavy grade of 
man i la paper. 

(h) Envelopes made of a medium quality of waterproof paper. 

(c) Envelopes made of a thin parchment paper. 

(c/) Envelopes made of the same quality of parchment paper as for 
the preceding series, l)ut paraffined previous to being tilled with seed. 
The packages were then sealed by redipping the open ends. 

{<} Envelopes of parchment paper, as for the two preceding series, 
except that the envelopes were first tilled with seed, sealed, and then 
the entire package was dipped in paraffin at a temperature of from 
55^ to 60^^ C. 

Samples of all of these packages were then stored under trade con- 
ditions and in dry rooms in Ann Arbor, Baton Rouge, and Mobile. 
The exact conditions of storage in the different places were the same 
as desciibed on pages 49 and 50. 

The samples were put up on May 20, 1901. The period of storage 
ended on November 26, having continued 190 days. Unfortunately, 
no special precautions were taken to dry the seeds. They were simply 
air-dried samples; hence they contained a quantity of moisture suffi- 
ciently large to give rise to an increased relative humidity of the 
confined air in the paraffined packages. This increased humiditj" was 



EXPERIMENTS IN KEEPING AND SHIPPING. 



0)9 



accoini)anied by a greater activity within tlie cells, and con.sequently 
by a greater deterioration of vital force. For this reason the results 
are not as definite as the conditions warrant. Nevertheless, .some 
important facts were brought out by the experiments which justify 
their l)eing discussed and tabulated (in part) at this time. 

Table XXVII. — ■Vitality of seed preservedin paraffined packages. 





Trade conditions, seeds put up in- 


Dry room, seeds put up in — 


Kind of seed. 


Paraffined 
envelopes. 


Parchment 
envelopes, 
then dip- 
ped in par- 
affin, at 
50° to 60° C. 


Seedsmen's 
packages. 


Paraffined 
envelopes. 


Parchment 
envelopes, 
then dip- 
ped in par- 
affin, at 
50° to 60° C. 


Seedsmen's 
packages. 


Cabbage: 

Ann Arbor, Mich 


Pi r cent. 
91 

30. 5 
70 

89. 5 
SO 
Si. 5 

91 


1 


Per cent. 
90 

.57. 5 
63 

89.5 

75 

77.5 

90 

4 

20 


Per cent. 

86.5 

8.5 

22.5 

96.5 

64 

74 

93 




Per cent. 
90.6 
38 
73.5 

91.5 

78 
82 

91. 5 

5 


Per cent. 
85.5 
50.5 
79.5 

90 
78. 5 
73.5 

89 
4.5 
40 


Per cent. 
86.5 
5 


Baton Roiige, La 

Lettnce: 

Ann Arbor, Mich 


35.5 

93 
61.5 


Baton Rouge, La 

Onion: 

Ann Arbor, Mich 


72.5 

89 



Baton Rouge, La 







.59. 39 


62. 94 


49.44 


61.11 


65.66 


49. 22 







In the first place, the injury resulting from the effect of the climatic 
influences is quite well marked in the above table. The conditions at 
Mobile and Baton Roug-e were much more detrimental to the life of 
the seeds than were the conditions at Ann Arbor. Secondly, the dif- 
ferences in the preservation of vitality of those seeds stored under 
trade conditions and of those kept in dry rooms were much less marked 
than they were in earlier experiments. This is probably accounted 
for by the marked difference in the two seasons. The summer of 1900 
was extremely wet in the vSouth, especially at Mobile, while the sum- 
mer of 1901 was exceptionally dry. Concerning the conditions Zim- 
mer Brothers wrote on November 26, 1901, as follows: 

We do not think you will find much difference in the two packages. The season 
this year has been very dry, with no rain since the big August storm; in fact, we do 
not remember such a dry season in thirty years. 

Althoug-h the season was exceptionally dry at Baton Rouge and 
Mobile, the loss in vitality was very g'reat in comparison with the loss 
at Ann Arbor, demonstrating very clearly that climatic influences play 
a very important part in the storage of seeds. 

This ta})le shows the relative resisting powers of lettuce, cabbage, 
and onion seed, the lettuce being most resistant and the onion least 
resistant, as shown in a preceding table. However, the chief purpose 



70 THE VITALITY AND GERMINATION OF SEEDS. 

of this series of experiments was to demonstrate the rehxtivo >ahje of 
different packages as a means of putting up seeds. 

In Table XXVII it will he observed that the results obtained from 
the waterpi'oof and parchment paper envelopes have been omitted. 
These omissions have been made ])ecause the results were practically 
identical with those of the ordinary seedsmen's packets; but the com- 
parisons to be made ])etween the ordinary paper packets and the 
paratlincd packages are w^orthy of consideration. Tlie envelopes that 
were paraffined after being" filled with seed gave the best results. 
This difference, however, was due not to the special treatment but 
to the higher melting- point of the paraffin. The average percentages 
of germination of the three samples of seed kept under trade con- 
ditions in the three localities were 59.39 per cent for the envelopes 
previously paraffined, 62.9-1 per cent for the envelopes dipped in 
paraffin after being filled with seed, and -idA-i: per cent for the seeds- 
men's envelopes. In dry rooms the results were 61.11, 65.66, and 
49.22 per cent, respective^. These averages were somewhat higher 
than the true conditions of Baton Iloug-e and Mobile warrant, as the 
results of the germination tests from all of the packages retained at 
Ann Arbor showed but little variation. Taking the three samples of 
seed which were stored under trade conditions in Mobile, the average 
percentage of germination was 21.2 for the seed from the nonparaftined 
package and 45. 5 per cent for the seed from the paraffined package, show- 
ing a loss in vitality of 77.3 and 49.5 per cent, respectively, considering- 
the germ ination of the Ann Arbor sample as a standard. At Baton Kouge 
the results were slightly better; the average percentages of germination 
were 32.2 for the seeds from the nonparaffined and 53.5 per cent for 
the seeds from the paraffined packages, representing- a loss in vitality 
of 65 and 40.5 per cent, respectively. While in either case the loss 
was very great, still the advantages of the paraffined packages are 
worthy of consideration for the reason that a prolongation of life for 
only a few weeks is frequently of the greatest importance, particularly 
in districts where much fall planting is done. 

In this connection ma}^ l)e given the results of some other tests, 
which really were a part of this same experiment, but included onl}^ 
onion seed. This seed was put up in seedsmen's envelopes and in 
paraffined envelopes like those previously described. In addition, 
seed was also put up in small bottles, which were corked. These 
packages were kept in a small box within a. suit case carried on two 
trips across the Atlantic and on a tour tlirough Central Europe, thus 
subjecting them to very varia])le conditions. Germination tests 
gave the following results: Seed from the ordinary packages, 77 per 
cent; paraffined envelopes, 90 per cent; l)ottles, 91 per cent. 

To test more thoroughly the keeping (qualities of seeds in paraffined 
packages and in ])ottles, anotlier series of experiments was begun on 
December 20, 1901. For these tests onlv cabbaa'e and onion seeds 



EXPERIMENTS IN KEEPING AND SHIPPING. 



71 



were used, but each with three dift'e rent deo-rees of moisture: (1) Seed 
from the original packages, i. e. , air-dried samples, the cabbage hav- 
ing a water content of 5.80 per cent, and the onion 6.48 per cent. 
(2) Air-dried sampk's were exposed in a moist atmosphere under a bell 
jar for two da3's, during which time the cabbage absorbed 1.83 per 
cent of water and the onion 2.41 per cent, thus raising the water con- 
tent to 7.63 and 8.89 per cent, respectivel3^ (3) Air-dried seeds 
which were dried in an incul)ator for eight days at a temperature vary- 
ing from 27 ' C. to 39° C. During this interval 2.05 per cent of water 
was expelled from the cabbage and 3.11 per cent from the onion seed, 
leaving a water content of only 3.75 per cent in the former and 3.37 
per cent in the latter. 

Each of the samples, treated as just described, was put up in three 
different kinds of packages: (1) Seedsmen's regular seed envelopes. 
(2) Similar envelopes which were paraffined, after being filled with 
seed, at a temperature of from 70" to 75° C. The melting point of the 
paraffin was 53° C. (3) In bottles which were closed with firm cork 
stoppers. 

One of each of the above packages was then stored at Mobile under 
trade conditions and in a basement; likewise at Ann Arbor in the 
herbarium room of the botanical laboratory, in a greenhouse, and in 
an incubator maintained at 40° C. The duration of this experiment 
was 131 days, from December 20, 1901, to April 30, 1902. The results 
of the germination tests are given in Table XXVIII. Two percentages 
have been given for the control sample, one for Ann Arbor and the 
other for Mobile. This was necessary since the two series were tested 
at different times and comparisons can not be made interchangeably 
between the two. 



Table X^X^VIII.— Vitality of cabbage and onion seed as preserved in various kinds of 
packages and sidjected to different conditions of storage. 

[Germination of control samples — Ann Arbor: Cabbage, 81.7 per cent; onion, 74 per cent. Mobile: 
Cabbage, 88 per cent; onion, 8-1.5 per cent.] 





Special treat- 
ment of 
package. 


Percent- 
age of 
water 
content 
of seed. 


Percentage of germination. 




Ann Arbor, Mich. 


Mobile, Ala. 


package. 


Botan- 
ical 
labo- 
ratory. 


Trade 
condi- 
tions. 


Green- 
house. 


Incuba- 
tor at 
40° C. 


Trade 
condi- 
tions. 


Base- 
ment. 


Cabbage: 


None 


5.80 
5.80 
5.80 
7.63 
7.63 
7.G3 
3.75 
3.75 
3.75 


81. 
80.0 
79.5 
85.5 
80.5 
80.5 
76.0 
80. 
83.0 


81.0 
79.0 
85.0 
80.5 
82.0 
85.0 
85.5 
8J.0 
8-1.0 


68.0 
85.5 
85.0 
65. 5 
83.5 
86.5 
67.0 
76.0 
74.0 


72.5 

62.0 
68.5 
74.5 
69.5 
48.0 
73.0 
71.0 
64.5 


60.0 
87.5 
84.0 
64.5 
86.5 
82.0 
64.0 
82.5 
82.5 


10.0 


Do 


Paraffin 

Corked 

None 


52.5 


Bottle 


84.0 


Envelope 


15.5 


Do 


Paraffin 

Corked 

None 

Paraffin 

Corked 


46.5 


Bottle 


91.5 


Envelope 

Do 


9.0 

78.0 


Bottle 


85.0 



72 



THE VITALITY AND GERMINATION OF SEEDS. 



Table XXVIII. — Vita/ili/ ofcahiHigr and onion seed as preserved in various kinds of 
packages and snhjecied to different kinds of storage — Continued. 





Special treat- 
ment of 
package. 


Percent- 
age of 
water 
content 
of seed. 


Percentage of germinatien. 




Ann Arbor, Mich. 


Mobile, Ala. 


package. 


Botan- 
ical 
labo- 
ratory. 


Trade 
condi- 
tions. 


Green- 
house. 


Incuba- 
tor at 
40° C. 


Trade 
condi- 
tions. 


Base- 
ment. 


Onion: 


None 


(!. 48 
G.4S 
0. 4.S 
S. S9 
8. 89 
8. 89 
3..S- 
3.37 
3.37 


78.5 
76.5 
73.5 
74.5 
74.5 
78.0 
(>1.5 
75.5 


69.5 
66.5 
71.5 
60.0 
66. 
OS. 
63. 5 
7'i. 5 
71.0 


3.5 
67.0 
60. 
11.5 
.56.0 
67.5 

8.5 
.58. 
77.0 


47.0 

4.5 

64.0 

•28.0 

9.0 

3.0 

? 6.0 

? 9.0 

59. 5 


19.5 
83.0 
86.0 
21.0 
74.5 
77.5 
17.0 
77.0 
84.5 


10.0 


Do 


Paraffin 

Corked 

None 


27.0 


Bottle 


82.5 




2.5 


Do 


Paraffin 

Corked 

None 


21.0 


Bottle 


78. 5 




6.0 


Do 


Paraffin 

Corked 


60.5 


Bottle 


81.5 



Manj^ of the points brought out b}" this table are vcr}' similar to 
those of the preceding- one, yet the differences are sufficientl>' marked 
to justify its being given in this connection. The seeds stored in the 
botanical laboratory and those subjected to trade conditions at Ann 
Ar))or have germinated practically the same, the cabbage slightly 
favoring trade conditions and the onion being better preserved in the 
laboratory. But a comparison of the trade conditions at Ann Arbor 
and Mobile in the unprotected packages shows the same wide variation 
that has been already pointed out. 

The advantage of drying is not very clearly )>rought out in this 
table; in many cases there seems to have been a slight injurj'^ as a 
result of the high temperature at which the drying was done. Una- 
voidably the temperature at that time reached 39° C, which, as has 
already been stated, is slightly above the maximum to which seeds 
can be subjected for any considerable time without injury. The 
injury due to heat is ver}^ evident in the samples stored in the incu- 
bator maintained at 40" C, this injury being more apparent with the 
increased moisture, especially in the paraffined package and in the 
bottle. However, on the whole the percentages of germination are 
higher for the dried seed than for the seed which had absorbed an - 
additional quantity of moisture; and, indeed, tlie comparison should 
properly be made with these two, for seeds as they are usually stored 
contain even higher percentages of moisture than either the cabbage 
or lettuce after they had absorbed the additional amount of water. 

But the chief purpose of the present experiments was to determine 
the relative advantages of envelopes, paraffined packages, and bottles 
as methods of putting up seed in order that vitality might l)e pre- 
served for a longer time. This comparison is best made by consider- 



experimp:nts in keeping and shipping. 



75 



ino- the vitality of the ,seod stored in the greenhouse at Ann Arbor and 
under trade conditions at Mobile. It will be readily seen that the 
vitality of the seed from the unprotected packages was greatly reduced, 
while those from the parafhned envelopes and from the bottles germi- 
nated nearl}' as well as the controls. These differences are better rep- 
resented diagrammatically, as follows: 



Bkujram represent ing ilie jwrcentarjes of gerwination of cabbage seed irhen treated as 

described. 



Kind of 
package. 


Special treat- 
ment of 
package. 


Percent- 
age of 
water 
content 
of seeds. 


Ann Arbor, Mich., green- 
house. 


Mobile, Ala., trade 
conditions. 


Envelope 




5.80 
5.80 
5.80 
7.63 
7. (13 
7. (53 
3.75 
3.75 
3.75 
5. SO 


73.3 


60 


Do 


Paraffined 

( ;orked 


92.1 


87.5 


Bottle 


91.5 


.S-1 


Envelofn' 


70. 5 


64. 5 


Do 


Paraffined 

Corked 


89.9 


,8C). 5 


Bottle 


93.1 


82 






Envelope 


72.1 


64 




Paraffined 

Corked 

Original pack- 
age. 




Do 


81.. s 


82 5 


Bottle 


79.7 


,H2. 5 


Control sample . 


8.S 


8,S 









Diagram represenling the percenlages of germination (f onion seed ivhen treated as described. 



Kind of 
package. 


Special treat- 
ment of 
package. 


Percent- 
age of 
water 
content 
of .seeds. 


Ann Arbor, Mich., green- 
house. 


Mobile, Ala., trade 
conditions. 






6.48 
6.48 
6.48 
8.89 
8.89 
8.89 
3.37 
3.37 
3.37 
6.48 


4 

76. 6 


19.5 


Do 


Paraffined 

Corked 


83 


Bottle 


68. 6 


.86 


Envelope 


13.2 
64 


21 


Do 


Paraffined 

Corked 


74.5 


Bottle 


77.3 


77.5 


Envelope 


66.3 


17 


Do 


Paraffined 

Corked 

Original pack- 
age. 


77 


Bottle 


8,s 


.84.5 


Control sample.. 


.S4.."i 


.S4. 5 









The percentages for Ann Arbor shown in the graphic representations 
are not the same as those given in the foregoing table. In the diagram 
they are directl}^ comparable with the results from the Mobile series, 



74 THE VITALITY AND GERMINATION OF SEEDS. 

all being* based on the vitalit}^ of the controls, as shown l)y the tests 
made at that time, the standard ])eino- ss per cent for the cabbage and 
84.5 per cent for the onion. 

A discussion here hardl}' seems necessary, as there can he no douljt 
that seeds retain their vitality much l)etter in moist climates if pro- 
tected from the action of the atmosphere. This ma}" ])e accomplislied 
by dipping- the packages in paraffin or ])y putting the seed in bottles. 
Disregarding the expense, V)ottles surpass paraffined envelopes as a 
means for the preservation of vitality, and also in tlie ease with which 
the seed can be put up. The results are more certain if care is exer- 
cised in selecting good corks. 

RESPIRATION OF SEEDS. 

From a practical point of view it lias been conclusivel}^ shown that 
moisture is the controlling factor in seed life. Seeds stored in a 
humid atmosphere soon lose their vitality, luit if carefulb,- dried and 
protected from moisture life is greatly prolonged. 

The question at once presents itself: In wliat way does the presence 
of increased quantities of moisture cause a premature death of the 
seed, or why is vitality prolonged if the water content of the seed be 
reduced? 

In a measure, the answer to this question is respiration. Seeds as 
we commonly know them absorb oxygen and give off carbon dioxid; 
that is, respire." During their respiratory activities the energy 
stored within the seed is readily evolved, the vital processes are 
destro3"ed, and life l)ecomes extinct. The intensity with which respi- 
ration takes place is largel}^ dependent upon the humidity of the sur- 
rounding atmosphere, which ultimately resolves itself into the amount 
of water in the seed. The respiratory activity is directly propor- 
tional to the quantit}^ of moisture al)sorbed l)y the seed up to a certain 
point, attaining its maximum during the process of germination. It 
has been found that a decrease in the water content results in a cor- 
responding dimiimtion in the intensity of respiration and consequently 
in a prolongation of the life of the seed as such. 

Bonnier and Mangin'' ^vere the first to show that respiration in liv- 
ing plants increases with an increase in the humidity in the surround- 
ing air. As this is true for growing plants, it is even more marked 
in stored seeds. Maquenne '" suggested that a reduction in moisture 
is accompanied by a reduction in respiration, l)ut at that time no 
experiments had been made to show that such was actuall}^ the case. 

aKolkwitz (Ber. d. dentsch. But. Ges., 19: 285-287, 1901) reports resxuratiou in 
recently gi-ound seeds. 

6 Ann. sc. nat. hot., ser. 7, 2: 365-380, 1885. 
cAnn. Agron., 26: 321-332, 1900. 



I 



RESPIRATION OF SEEDS. 75 

In 1832, Aug. P^-r. De Candolle wrote in the second volume of hi.s 
Physiologic Vegetale that the vitality of seeds would bo prolonged if 
they were i)uried sufficiently deep in the soil to protect them from 
oxygen (or air) and moisture. Unfortunately, De Candolle did not 
discover the true cause of this prolonged life, for nowhere did he 
make any reference to respiration. Nevertheless his general conclu- 
sions were properly drawn. De Candolle also stated that light acceler- 
ates evaporation in seeds and thus causes a premature death. Here, 
however, his results were wrongfully interpreted. These conclusions 
arc applica])le only in case of seeds that die if allowed to become dry. 
The real effect of light is to cause a slightly accelerated respiration 
and consequently a greater deterioration in vitalit3^ Jodin^' states 
that light accelerates respiration to a marked degree. His experi- 
ments were with peas which contained 10 to 12 per cent of moisture. 
Two samples of peas were placed, each under a bell jar, over mer- 
cury. One sample was kept in the light and the other in the dark. 
At the end of ■! years 6 months and 11: daj^s an analysis of the con- 
lined air from the sample kept in the light gave the following results: 

Peas, 3.452 grams, in air, in light: Percent. 

Oxygen 19.1 

Nitrogen 78. 6 

Carbon dioxid 1.2 

At the end of -1 years 7 months and 11 days an analysis of a sam- 
ple of air taken from the other chamber was as follows: 

Peas, 3.580 grams, in air, in dark: Percent. 

Oxygen 20. 8 

Nitrogen 79. 1 

Carbon dioxid 1 

The 3.152 grams of peas that were subjected to the influence of the 
action of light had absorbed, in the given time, 2.4 cc. of oxygen and 
produced 1.8 cc. of carbon dioxid. The seed kept in the dark showed 
but little signs of respiratory activity. Germination tests of the 
former showed the peas to be dead, while five peas from the sample 
kept in the dark germinated perfectly. 

While there is no question that light exerts some influence on respi- 
ration, still the above results do not furnish sufficient data to establish 
the fact that respiration practically ceases in the absence of light. In 
fact, experiments have shown that respiration is also quite marked in 
case of seeds stored in the dark, and the difl['erence is very slight if the 
same temperature be maintained. 

Van Tieghem and Bonnier, in their "Recherches sur la vie latente 
des graines,"* demonstrated that 7.976 grams of peas, sealed, in air, 

«Ann. Agron., 23: 433-471, 1897. 

6 Bui. See. bot. France, 29: 25-29, 1882. 



76 THE VITALITY AND GERMINATION OF SEEDS. 

in !i tiil>e, respired quite freely. Aftei' the hipsc of two yeai's an 
analysis of the confined air i^ave the following- rosidts: 

I'er cent. 

Oxygen 14. 44 

Nitrogen 81. 74 

Carl)on dioxid 3. 82 

These same seeds g-erminated 45 per cent and had increased ^-J-y of 
their original weight. 

In the experiments of the writer it was found that 40.11.50 grams of 
air-dried beans liberated 7.7 cc. of carbon dioxid in 370 days. The 
concentration of the carbon dioxid in the flask at the time the gas was 
drawn for analysis Avas 1.54 per cent. This sample of seed germinated 
97 per cent, and there was only a very slight retardation in germina- 
tion, which Indicated that the vitalit}' had not been materiall}" reduced. 
During this time there was a slight decrease in the weight of the seed — 
0.10 per cent. At the same time two check bottles were set up, one 
containing 40.1184 grams of beans known to be dead, and the other 
bottle containing nothing except air. Analyses of the air from these 
two bottles gave the same results as samples of air drawn from the 
laborator}. These preparations were kept in subdued light through- 
out the experiment. 

That respiration may take place in the dark, that it is ^ery intense 
if much moisture be present, and that intensive respiration is accom- 
panied b}^ a rapid loss in vitality is shown In' the following experi- 
ments. On April 3, 1900, samples of beans, ca])bage, carrot, lettuce, 
and onion were sealed, each in bottles of 250 cc. capacity, and were 
stored in a dark room which was maintained at a temperature of from 
20^ to 25° C. These samples were first carefully weighed and then 
placed in a damp chamber for 175 hours, so that an additional quantity 
of moisture could ])e absorbed. 

Control samples of air-dried seeds were also kept in sealed bottles 
and subjected to the same subsequent treatment. After the lapse of 
one 3'ear analyses of the confined gases and germination tests of the 
seeds were made, the results of which are given with the general 
details. 

Beans. — Of beans, 24.9994 grams absorbed 4.70 per cent of water 
while in the damp chamber. The respiration during the year was 
equivalent to 2.5 cc. of carbon dioxid. The loss in weight was only 
0.05 per cent, but the vitality had fallen from 100 to 86 per cent, as 
shown by the control. 

Cnhhage. — Of cabl)age seed, 10 grams, with an additional 9.79 per 
cent of water, were used for this test. During the 3'ear this sample 
of cabbage seed had given off 24 cc. of carbon dioxid, an equivalent of 
2.4 cc. of carbon dioxid per gram of seed per j^ear. The control 
sample germinated S9 per cent, Init this seed was dead. 



RESPIRATION OF SEEDS. 77 

Carrot. — Of carrot seed, 10 j>-rams were allowed to absorb during 
175 hours an additional 10.25 per cent of water. In one year 27 cc. of 
carbon dioxid were produced, giving a concentration of carbon dioxid 
of nearly 12 per cent. The deterioration in. vitality was from 84 to 
per cent, as compared with the control. 

Lettuce.— Oi air-dried lettuce seed, 10 grams were allowed to absorb 
an additional 8.87 per cent of water. During the experiment 19.5 cc. 
of carbon dioxid were formed, an equivalent of approximatel}^ 10 per 
cent of the original volume of the inclosed air. These seeds were all 
killed. The control sample germinated 94 per cent. 

Onion. — Of air-dried onion seed, 10 grams were allowed to absorb 
an additional 10.11 per cent of water. The seed gave off 26.5 cc. of 
carbon dioxid during the experiment and deteriorated in vitality from 
97 to per cent. 

A bottle containing 4 cc. of water was also sealed at the same time 
and served as a check for the other analyses. A sample of air taken 
from this bottle gave the same results as the original air sample. 

It is a matter of much regret that no analyses could be made of the 
air from the bottles which contained the check samples. These bottles 
contained the same weight of air-dried seeds as was used for the 
experiments. Unfortunately the seals on these bottles had become 
dry and admitted of an exchange of gases, so that the results were not 
reliable. 

Another series of experiments consisted in keeping onion seeds in 
sealed bottles for 1 year and 13 days, with the following results: 

{a) Fifty grams of air-dried seed were sealed, in air, in a bottle of 
500 cc. capacity. There was an increase in the weight of the seeds of 
0.1091 gram — slightly more than 0.2 per cent. An analysis of the 
inclosed gas gave: 

Per cent. 

Oxygen 12. 27 

Nitrogen 85. 87 

Carbon dioxid 1. 86 

{1)) Fiiiy grams of air-dried seed were sealed, in air, in a 500 cc. 
bottle, with 4 cc. of water in a small test tube at the bottom of the 
bottle. Nearly all of the water was absorbed by the seeds, there 
being an increase in weight of 3.6475 grams, or 7.3 per cent. The 
composition of the inclosed air was: 

Per cent. 

Oxygen None 

Nitrogen 86. 65 

Carbon dioxid 13. 35 

The oxygen had all been consumed and the seeds were all dead. 

{c) Fifty grams of onion seed were sealed in a 500 cc. bottle, in a 

Lorc. 



78 THE VITALITY AND GJ:RMINATI0N" OF SEEDS. 

mixture of illuniiiiatino' gas and air. The increase in weight was only 
0.01 per cent. An analysis of the inclosed gas was as follows: 

Per eeiit. 

Oxygen : 3. 23 

Carbon dioxid 1. 21 

Methane and nitrogen 95. 96 

{d) Another 50-grani sample of onion seed, belonging to a different 
series, was sealed in a bottle of 300 cc. capacity, and showed the 
following composition of the inclosed air: 

Per cent. 
Oxygen 8.02 

Nitrogen 85. 17 

Carbon dioxid 6. 81 

In only one case was there an}^ deterioration in vitality, namely, 
where the large (juantity of moisture was present. The other samples 
germinated normally. The seed kept in the illuminating gas germi- 
nated even better than the control. 

In all of the bottles there was a marked decrease in pressure, show- 
ing that the volume of oxygen al)sorbed was much greater than the 
volume of the carbon dioxid given off. 

During respiration certain chemical changes must be taking place 
which exert a marked influence on the vitalit}^ of seeds. What these 
changes are is a (juestion 3^et to l)e solved. The protoplasts of the 
individual cells gradually but surely ])ecome disorganized. C. De 
Candolle" takes the view, in discussing the experiments of Van Tieg- 
hem and Bonnier, that during respiration life is simply subdued. 
But the period of suljdued activity, he says, is comparatively short, 
for respiration soon ceases and life becomes wholly latent. As a result 
of his own experimiMits in storing seeds at low temperatures he con- 
cludes that seeds cease to respire and l)ecome completely inert; in 
which case they can suffer any degree of reduction in temperature 
without ])eing killed. The killing of the seeds experimented with 
(lobelia) he attributes to the fact that the protoplasm had not l)ecome 
inert, l^ut simply sul)dued, and the seeds were thus affected ])y the low 
temperature. 

As a result of later experiments C. Do Candolle,^ in keeping some 
seeds inidcr mercury to exclude air, concludes that *■' seeds can contimie 
to subsist in a condition of complete vital inertia, from Avhich they 
recover whenever the conditions of the surrounding medium permits 
their 'encu-gids,' or living masses of their cells, to respire and assim- 
ilate." He compares the protoplasm in latent life to an explosive 
mixture, having the faculty of reviving whenever the conditions are 
favorable. This comparison seems rather an unfortunate one; yet, 
within a certain measure it is probabl}^ true. 

« Revue Sdentifi(iue, ser. 4, 4: 321-326, 1895. 
^Pop. Sci. Montlily, 51: 106-111, 1897. 



RESPIEATION OF SEEDS. 79 

It is now quite generally accepted that respiration is not absolutely 
necessary for t^ie maintenance of seed life, notwithstandino- the fact 
that Gray contended that seeds would die of suffocation if air were 
excluded/' The experiments of Giglioli'' in keeping seeds of Medicago 
sativa immersed in various liquids for approximately sixteen years, 
after which many responded to germination tests, has done nnich 
toward demonstrating the fact that seeds can live for a considerable 
time in conditions prohibiting respiration. 

Kochs'" succeeded in keeping seeds for many months in the vacuum 
of a Geissler tube without being able to detect the presence of any 
carbon dioxid, and consequently he concluded that there was no gas 
given off l>y intramolecidar respiration. 

Romanes <^ kept various seeds in vacuum in glass tubes for 15 months 
and the seeds were not killed. However, his vitality tests can not be 
considered as entirely satisfactory. In the first place, the number of 
seeds used (ten) was too small; secondl}^, the variations in the results, 
even in the controls, indicate that the samples were not of very good 
quality. 

In the experiments of the writer cabbage and onion seed were kept 
in a vacuum over sulphuric acid for 182 days. During this time all of 
the free Avater had ])een extracted from the seed. When again con- 
nected with a vacuum gauge the dial showed that there was not the 
slightest change in pressure, and that consequcntl}- no evolution of 
gases had taken place. The cabbage germinated 75 per cent and the 
onion 73 per cent as compared with 81 and 71 per cent, respectively, 
for the controls. 

The results of the various experiments above given demonstrate 
quite full}^ that the vitality of seeds, as we commonly know them, is 
not interfered with if they are kept in conditions prohibiting respira- 
tion. Brown and Escombe'' hold that all chemical action ceases at 
temperatures of liquid air. They accordingly conclude that " any 
considerable internal chemical changes in the protoplasts are rendered 
impossible at temperatures of —180° to —190° C, and that we must 
consequentl}^ regard the protoplasm in resting seeds as existing in an 
absolutely inert state, devoid of any trace of metabolic activit}^ and 
yet conserving the potentialit}' of life * * * And since at such low 
temperatures metabolic activity is inconceivable an immortality of the 
individual protoplasts is conceivable providing that the low tempera- 
tures be maintained." 

«Amer. Jour, of Sci., 3cl series, 24: 297, 1882. 
«> Nature, 52: 544, 1895. 
cBiol. Centrbl., 10: 673-686, 1890. 
f^Proc. Roy. Soc, 54: 33.5-337, 1893. 
sibid., 62: 160-165, 1897-98. 



80 THE VITALITY AND GERMINATION OF SEEDS. 

Giglioli" arrived at practically the same conclusion.s when he said: 

It is a coniinon notion that life, or capacity for life, is always connected with con- 
tinuous chemical and i)hysical change * * * The very existence of living matter is 
supposed to imply change. There is now reason for believing that living matter 
may exist, in a completely passive state, without any chemii'al change whatever, 
and may therefore maintain its special jiroperties for an indefinite time, as is the 
case with mineral and all lifeless matter. Chemical change in living matter means 
active life, the wear and tear of which necessarily leads to death. Latent life, when 
completely passive in a chemical sense, ought to be life without death. 

But even thouo-h ordinary respirator}^ exchanges are not necessary 
for the maintenance of vitalit}^, and granting that intramolecular 
respiration does not occur in the resting protoplasts, there is no exper- 
imental evidence pointing to the fact that all chemical action ceases, 
although some writers, as has already been shown, maintain the view 
that living matter ma}^ exist in a completely passive state. If "com- 
pletely passive" meant devoid of respirator}- activities none would dare 
dissent; l)ut that seeds are entirely quiescent under an}- known con- 
ditions has not been proved. To conceive of all activity ceasing 
within the seed under certain conditions, and that with such cessation 
of activity an inunortality of the seed is possible, i. e., if such con- 
ditions continue to exist, is, from our present knowledge of the chem- 
istry and behavior of the living cell, impossil)le. In Giglioli's experi- 
ments respiration w^as undoubtedly prevented, and, according to his 
own conchisions, vitality sliould have been preserved, for he says "in 
the al)sence of any chemical change the special properties ma}' lie main- 
tained indefinitely.'' But, in his own experiments, the special prop- 
erties were not maintained, foi- all of the seeds with which he experi- 
mented deteriorated very much, and many died. Granting that those 
which suffered the greatest loss in vitality were injured by the pres- 
ence of the particular gas or li(iuid used there remain no means of 
accounting for the deterioration in those giving the highest percentages 
of germination. His experiments were made for the most part with 
Medicago sativa^ which, under ordinary conditions of storage, is espe- 
cially long lived. Samek '' has shown that seed of Medicago satioa 11 
years old was capai)le of germinating 51 per cent. Giglioli succeeded 
in getting a germination of only 56.56 per cent after a little more than 
16 years in hydrogen, and 81.20 per cent when they had l)een kept in 
carbon monoxid. Jodin ^" kept peas immersed in mercury for 1^ years 
and they germinated 80 per cent. After 10 years the vitality had 
fallen to 41 per cent. Nobbe obtained a germination of 33 per cent 
in peas 10 years old which had been stored under normal conditions. 
Likewise the experiments of Brown and Escoml)e do not justify the 

« Nature, 52: 544-545, 1895. 

''Tirol, landw. Bliitter, 13: lHl-162, 1894. 

cAnn. Agron., 23: 433-471, 1897. 



RESri RATION OF SEEDS. 81 

coiu'lusioiis which they have dniwn. It is now definitely known that 
all chcuiical actions do not cease at the temperature of li(iuid air. Thus 
it can not ])e o-ranted that the protoplasm becomes inert as a result of 
the reduction in temperature. Maquenne " more nearl}'^ expressed the 
true conditions applicable to low temperatures when he wrote that 
with dessication, at low temperatures, seeds are transformed from a 
condition of diminished activity into a state of suspended life. But 
tliere are still other factors to be considered. The vegetative functions 
may cease, metabolic processes may be at a standstill, intramolecular 
respiration need not exist, yet vitality is not, nor ever has been, pre- 
served; sooner or later life becomes extinct. What does this signify? 
The gradual process of devitalization means chemical change, and 
chemical change means activity within the cells. We nuist not forget 
the great complexity of the composition of the protoplasmic bodies 
which go to make up a seed. The chemistry of the living cell is still 
surrounded bj^ many difficulties and is likewise tilled with many sur- 
prises, and before the question of the vitality of seeds can l)e under- 
stood a more comprehensive knowledge of both the functions and 
composition of the cell contents is necessary. 

It is well known that all organic compounds are made up of a very 
few elementary substances, but the numerous and obscure ways in 
which they are put together furnish questions of the greatest per- 
plexity. Substances having the same elements may difl'er widely as 
to their properties. Moreover, isomeric substances — i. e., those hav- 
ing the same elements in the same proportions, giving an equivalent 
molecular weight — are usually very different in their chemical reac- 
tions and physiological functions. As yet this intramolecular atomic 
rearrangement is but vaguely understood, and the writer ventures to 
suggest that with a more comprehensive knowledge of the chemistry 
of the living cell some such chemical activity will be discovered. 
With these discoveries will come, perhaps, an understanding of the 
devitalization of seeds, and with it the theory of the immortality of 
seeds will vanish. 

SUMMARY. 

(1) Seeds, like other living organisms, respire when subjected to 
normal conditions of storage. 

(2) Respiration means a transformation of energy, and consequently 
a premature death of the seed. 

(3) Within certain limits respiration is directly proportional to the 
amount of water present in the seeds and to the temperature at which 
they are stored. 

(4) By decreasing the watei- content of seeds respiration is reduced 
and vitality greatly prolonged. 

«Compt. Rend., 134: 1243-1246, 1902. 
25037— No. 58—04 6 



82 THE VITALITY AND GERMINATION OK WEEDS. 

(5) In most seeds the (Quantity of oxyj^-eii a])Sorb(Hl o-roatly exceeds 
the ([uaiitity of carbon dioxid evolved. 

(()) Respiration is nearl}^ as active in the dai-k as in the lioht. 

(7) Respiration apparently is not necessary for the maintenance of 
seed life. 

(8) A cessation of respiration does not mean a cessation of chemical 
activities. 

ENZYMES IN SEEDS AND THE PART THEY PLAY IN THE 
PRESERVATION OF VITALITY. 

During the past decade the so-called unorganized ferments have 
taken an important place among the subjects of biological research. 
Our knowledge of their wide distribution has increased many fold. 
The part they play in both ana])olism and catabolism has furnished us 
many surprises, but with all of the work that has been done our knowl- 
edge of these most complex compounds is very limited. 

The part that enzymes pla}^ in the processes of germination is of the 
utmost importtmce. It is now quite well understood that they are 
developed as germination progresses. They act on the most complex 
reserve food products, converting them into simpler substances that 
can be more readily utilized by the growing seedling. 

However, even in this connection there is a great diversity of opinion, 
especially as to their distribution and enzymic action within the endo- 
sperm itself. Puriewitsch," Griiss,'' and Ilansteen '^ are cited by Brown 
and Escombe'' as holding the view that the amyliferous cells of the 
endosperm of the grasses can digest their reserve materials independ- 
ently of any action of the embryo — i. e., the starch -bearing cells are 
living cells and secrete enzjnnes in the grasses as well as in the coty- 
ledonous cells of Zv/pinus, PJiaseohts, and Btcin us. In 1890, Brown 
and Morris' did not find such to be the case; but the results of Furie- 
witsch, Griiss, and Ilansteen led to a duplication of the experiments 
by Brown and Escombe in 1898. At this time they demonstrated that 
the amyliferous cells play no part in the chemical changes which take 
place during the process of germination, but on the contrary that the 
enzymic action in the endosperm of the grasses is confined to the 
aleuron layer. 

But the purpose of the present paper is not to consider the localiza- 
tion of the particular enzyme, and much less the action of enzymes 
during germination. At this time quite another question is to be 

f'Pringsheims Jahrb., 31: 1, 1897. 

J'Landw. Jahr1)iicher, 1896, p. 385. 

<^ Flora, 79: 419, 1894. 

f^Proc. Roy. Soc, 63: 3-25, 1898. 

«Jour. Chem. Soc, London, 57: 458-528, 1890. 



ENZYMES IN 8EEDS. 83 

considered, viz, In what way do enzymes function in the presei'vation 
of vital it}'? 

Maquenne" points to the view tliat the vitality of seeds is dependent 
on the sta])ility of the particular ferment present. He attributes the 
prolongation of vitality in seeds that are kept dry to the l)etter preser- 
vation of the enzymes. This view has been largely strengthened as a 
result of the investigations made ])y Thompson,^ Waugh,'' Sharpe,'' and 
others, in which they have show'n that the artiticial use of enzymes 
may greatly increase the percentage of germination in some old seeds. 
By the use of diastase the percentage of germination of 12-year-old 
tomato seed has l)een increased more than 600 per cent. 

If the suggestions made by Maquenne were true in ever}"^ sense, then 
dead seeds should be awakened into activity b}^ artificially supplying 
the necessary enz3mies; but this can not be, or never has been, accom- 
plished. True, many experiments have been recorded in which a 
greater percentage of seed has been induced to germinate by the judi- 
cious use of commercial enz3'mes than by the ordinary methods of 
germination; but this treatment is applicable only where the vital 
energy is simply at a low el^b and does not in any way affect dead 
seeds. The experiments of the writer with naked radicles from the 
embryos of living and dead beans have shown the presence of enzymes 
in both. The carefully excised radicles were ground and macerated 
in water for one hour. The filtrate was then added to dilute solutions 
of starch paste. The solutions from the living embryos gave rise to 
an energetic hydrolytic action. In all cases hydrolysis was sufficiently 
advanced to give a clear reaction with Fehling's solution. The solu- 
tions extracted from the radicles from the dead beans also gave reac- 
tions sufficiently clear to indicate that there was still some ferment 
present. '^ 

However, the hydrolysis was scarcely more than begun, giving only 
a brown color with iodin, but not reacting with Fehling's solution. 
Results of a similar character were obtained from portions of the seed 

«Ann. Agron. 26: 321-332, 1900; Compt. Rend., 134: 1243-1246, 1902. 

&Gartenflora, 45: 344, 1896. 

c Mm. Report, Vt. Agr. Exp. Sta., 1896-97, and Science, N. S., 6: 950-952, 1897. 

<' Thirteenth Annual Report, Mass. Hatch Exp. Sta., Jan., 1901, i^p. 74-83. 

«' This was a sample of "Valentine" l)eans grown in 1897. The same year thej'^ 
tested 97.3 per cent. In March, 1898, the same sample tested 87 per cent. At this 
time they were sent to Orlando, Fla., where they remained until May 8, 1899, 
approximately fourteen months. The beans were then returned and numerous 
germination tests were made at irregular intervals, but in no case was there any indi- 
cation of vitality. Several samples were also treated with "Taka" diastase (solu- 
tions varying in strength from 2 to 10 per cent), but none was stimulated into 
germination. The radicles were tested for enzymes in the spring of 1902, nearly 
three years after the beans lirst failed to germinate, at which time they were nearly 
6 years old. 



84 THE VITALITY AND GP]RM1NATK)N OF SEEDS. 

taken from the point of luiion of the axis and the cot^dedons. These 
possessed stronger hydrolytic powers, the preparations from the livinj^ 
and dead l)eans each giving' clear reactions with Fehling\s sohition. 
A third series of tests was made b}^ stopping the germination of beans 
when the radicles were from 1 to 1.5 cm. long. These were tlien kept 
quite dry for nearl}- seven months, after which the dessicated radicles 
were broken o& and macerated like the above. This solution was then 
allowed to act on starch paste, and the transformations were almost as 
rapid and complete as when a 1 per cent solution of commercial '* Taka" 
diastase was used. 

These results lead one to believe that the loss of vitality in seeds is 
not due to the disorganization of the enzymes present. There is some- 
thing more fundamental and probably more complex to which we nuist 
look for this life-giving principle. True, as Maquenne has suggested, 
there is a close relationship between the loss of vitalit}^ in seeds and 
the decomposition of enzymes. 

In order to determine what such a relationship might signify, the 
following series of experiments were made: 

Beans, peas, cabbage, lettuce, onion, phlox, and pansj^ seed, with 
definite quantities of good commercial " Taka " diastase, were put up 
in bottles of 120 cc. capacity, as follows: 

(1) In bottle closed with cork stopper. 

(2) In bottle closed with cork sto]:)per and paraifined. 

(3) 0.5 cc. of water in the bottle with the seeds and the diastase, the 
bottle sealed with paraffin. 

(•1) 1 cc. of water in the bottle with the seeds and the diastase, the 
bottle sealed with paraffin. 

(5) 2 cc. of water in the bottle with the seeds and the diastase, the 
bottle sealed with paraffin. 

(6) 3 cc. of water in the bottle with the seeds and the diastase, the 
bottle sealed with paraffin. 

(7) i cc. of water in the bottle with the seeds and the diastase, the 
bottle sealed with paraffin. 

The water in each case was carefully added on small strips of filter 
paper and never were the seeds or the diastase wet, only becoming 
gradually moist as the water was absorbed. 

These different preparations, each containing one of each of the sam- 
ples of seeds and a definite quantity of the dry powdered diastase, 
were then maintained at the temperature of the laboratory for a period 
of 85 days. At the end of that time the vitality of the seeds was deter- 
mined and simultaneously the h3'drol3^tic power of the diastase was 
ascertained. The results of the germination tests are given in Table 
XXIX. The effect of the increased (|uantity of moisture on the diastase 
is given in the discussion following the table. 



ENZYMES IN SEEDS. 



85 



Tahle XXIX. — Lous in, vitality of seeds with varying degrees of moisture when kept at 

ordinary room teitiperature. 

[Duration of experiment, S5 days.] 



Labor- 


Preparation 
of sami)le. 


Amount 
of water 
added. 


Percentage of germination. 


atory 
num- 
ber. 


Beans. 


Peas. 


Cabbage. 


Onion. 


Phlox. 


Pansy. 


Average 

of all 
samples. 


1547 
1548 
1549 
1550 
1551 
1652 
1553 


Control" ... 

Corked 

Paraffined.. 

do 

do 

do 

do 

do 


cc. 
None . . . 

None . . . 

None . . . 
0.5 
1.0 
2.0 
3.0 
4.0 


9(;. 

98.0 
9C). 
96.0 
96.0 
96. 
94.0 
90.0 


90.0 
96. 
92. 
92.0 
88. 
86. 
94.0 
81.6 


91.5 
91.0 
91.5 
89.0 
89.0 
78.0 
65.0 
54.5 


95.0 
92. 5 
93.0 
88.8 
64.0 
13.0 
2.5 
.0 


41. 25 
52.0 
39.5 . 
28.5 
12. 5 

.5 

.5 

.0 


46.0 

32.0 

31.0 

25. 5 

18.0 

2.5 

.5 

.0 


76. 6 
76.9 
73.8 
69. 9 
01. 2 
46.0 
46.1 
37.6 



a The samples prepared, excepting the control, were in bottles of 120 cc. capacity. 

The above table shows that there was a gradual deterioration in 
vitality as the quantity of water was increased. All stages of injury 
were manifested, but it is not necessary to enter into a discussion of 
the table at this time, inasmuch as similar tabulations, showing the 
injurious effects of varying quantities of moisure on the seeds, have 
alread}' l)een given on page 38. This table is inserted here in order 
that a comparison can he made with the decomposition of the com- 
mercial diastase used and the loss in vitality of the seeds. 

For a determination of the diastasic activity various quantities of 1 
per cent " Taka" diastase solutions were allowed to act on definite quan- 
tities of a 1 per cent solution of starch paste, the whole being maintained 
at a temperature of from 45° to 48° C. Ten cubic centimeters of the 
starch solution were taken for each determination, and the amount of 
the diastase solution varied from one-half to 1, 2, 3, and 5 cc. In the 
control sample, consisting of diastase from the original bottle as it was 
kept in the laboratoiy, 2 cc. of the 1 per cent solution were sufficient to 
cause a complete hydrolysis of the 10 cc. of 1 per cent starch solution. 
In Nos. 1547, 1548, and 1549 the samples from the control bottle, the 
paraffined bottle, and the paraffined bottle containing 0.5 cc. of water, 
respectively, 3 cc. of the diastase solution were necessaiy for a com- 
plete hydrolysis. In Nos. 1550, 1551, and 1552 — that is, the samples 
from the bottles which contained 1, 2, and 3 cc. of water, respectively — 
the diastase was very much injured as a result of the increased quan- 
tit}^ of water in the bottle and 5 cc. of the diastase solution were 
required to h3'drol3'ze the 10 cc. of the 1 per cent starch paste. No. 
1553 — the sample from the bottle which contained the 4 cc. of water — 
showed that the diastase had been almost completely disorganized, 
inasmuch as the greatest quantity used (5 cc. of the 1 per cent diastase 
.solution) was only sufficient to cause a slight hydrolytic action. When 



86 THE VITALITY AND GERMINATION OF SEEDS. 

tested with iodine there was still a deep, purplish-hlue color. In this 
last case the average percentage of germination had decreased to 37.6 
per cent, as compared with 70.6 per cent for the control samples. 
Moreover, in the latter case, the onion, phlox, and pans}' seeds were 
killed. 

These results show that there is a remarkable uniformity between 
the loss in vitalit}' of seeds and the loss in the enzymic action of the 
"Taka'' diastase under similar conditions, but it does not furnish con- 
clusive evidence that the loss in vitality of the seeds is in any way 
governed b}' the particular enzymes present. In fact, the evidence at 
hand Ijetter suljstantiates the opposite view. In the first place dead 
seeds may still contain active ferments. Secondl}^ the prolonged sub- 
jection of seeds to the action of ether and chloroform is generally 
accompanied by a premature death, and if the seeds are moist the loss 
in vitality is nuich more marked. On the other hand, it is generally 
accepted that either of these gases exerts no injurious effect on the 
hj^drolytic action of the various ferments. Townsend « has shown that 
the action of diastase on starch paste is even more energetic in the 
presence than in the absence of ether, but in germination ether usually 
has a retarding influence. In some cases, however, growth is stimu- 
lated by the use of ether. 

In the third place enzymes can not })o the chief factors controlling 
the vitality of a seed, because the more sensitive growing point of 
the radicle suffers injury much in advance of the other portions of 
the seed. Not infrequently in making germination tests do we find 
that the growing tip of the embryo is dead, while other portions of 
the seed may still he living and capal)le of carrying on all normal met- 
abolic processes. The bean is one of the best examples for demon- 
strating this fact. Here the radicle may be entirely dead, yet the 
cotyledons may still be able to make some growth; but in all seeds 
where the growing tip is dead the remaining portion of the radicle 
may l>e li^'ing, in which case adventitious roots may be formed and 
growth may continue for a considerable time, though ver}^ rarely will 
a healthy seedling be developed. It thus seems quite clear that the real 
vital elements are closely associated with the growing point, and when 
this portion of the emlnyo is once dead the vital energy in the other 
parts of the seed is not of such a nature as to enable growth to con- 
tinue for any length of time. Even though the reserve food products 
are digested they can not be assimilated by the growing radicle, which 
should be the case were enzymes the chief elements to which the 
preservation of vitality is attributed. 

Enzymes play an important part in the vitality of seeds, and are 
undoubtedly necessarj^ for the normal development of a seedling, but 
the points above given show that the life of a seed is not entirely 

«Bot. Gaz., 1S9V), 27: 458-466. 



SUMMARY. 87 

dependent on the stability of the particular ferment or ferments 
present. There is something- more remote, possibly of a simpler but 
probably of a more complex composition, to which we must attribute 
the awakening of the metal )olic processes. Reference is not made 
here to the zymogenic substances which develop into the particidar 
ferment, for what has been said of the latter applies equally well to 
the former. If the zymog-ens were perfect!}' preserved the resulting- 
ferments would be developed normally and germination would continue 
in the usual manner. 

In conclusion, it ma^^ well be emphasized that no single element or 
compound can be isolated as the sole source of vitality in seeds. 
There must be a combination of factors, each of which plaj-s an 
important role in the preservation of vitality. The destruction of 
any one of these factors may upset the principles governing- the life 
of a seed, and consequently cause a premature death. 

It is quite probable that the nucleus is one of the most important 
organs governing vitality, for unless it continues to function no other 
growth can take place. Other parts of the cell, however, may be of 
equal importance. At all events all hope of future gain must come 
from more critical studies of the cell contents to know their chemical 
composition and possible reactions. A correct solution of these perplex- 
ing questions is nothing less than a determination of the fundamental 
principles of life. What will be the ultimate results no one is prepared 
to say. 

SUMMARY. 

(1) A seed is a living organism, and must l)e dealt with as such if 
good results are expected when put under favorable conditions for 
germination. 

(2) The first factoi-s determining the vitalit}" of a seed are maturity, 
weather conditions at the time of harvesting, and methods of harvest- 
ing and curing. 

(3) Immature seeds sown soon after gathering usuall}' genninate 
readily, but if stored they soon lose their vitality. On the other hand, 
well-matured seeds, harvested under favoral)le conditions, are com- 
paratively long lived when properly handled. 

(4) Seed harvested in damp, rainy weather is much weaker in vital- 
ity than seed harvested under more favorable conditions. Likewise, 
seed once injured will never regain its full vigor. 

(5) The curing of the various seeds is of the utmost importance, and 
great care should be taken to prevent excessive heating, otherwise the 
vitality will be greatly lowered. 

(6) The life period of any species of seed, granting that it has been 
thoroughly matured and properly harvested and cured, is largely 
dependent on environment. 



88 THE VITALITY AND GERMINATION OF SEEDS. 

(7) The average life of seeds, a.s of plants, varies greatly with difl'er- 
ent families, genera, or species, but there is no relation between the 
longevity of plants and the viable period of the seeds they bear. The 
seeds of some plants lose their vitality in a few weeks or months, 
while others remain viable for a number of 3'ears. 

(S) With special precautions and treatment there is no question that 
the life of seeds maj he. greatly prolonged beyond that which we know 
at present, though ne^er for centuries, as is frequently stated. Cases 
so reported can not be taken as evidence of the longevity of seeds. 

(9) It is known that seeds retain their vitality much better in some 
sections of the country than in others. Tlie part which climatic influ- 
ences play in the vitality of seeds is of much more importance than is 
generally supposed. 

(10) Experiments have shown that moisture is the chief factor in 
determining the longevity of seeds as they are commercially handled. 
Seeds stored in dry climates retain their vitality much ])etter than 
when stored in places having a humid atmosphere. 

(11) The deleterious action of moisture is gi-eatl}^ augmented if the 
temperature be increased. Not infrequentl}^ is vitality destroyed 
within a few weeks or montlis when the seeds are stored in warm, 
moist climates. If stored in a dry climate, the question of temper- 
ature within the normal range is of little moment. 

(12) The storage room for seeds as they are ordinarily handled 
should alwa3\s l)e dry. If seeds could l)e kept dry and at the same 
time cool, the conditions would be almost ideal for the preservation 
of vitality; but the difficulties to be overcome in order to secure a dry 
and cool storage room render this method impracticable. 

(13) The most feasible method for keeping seeds dry and thus insur- 
ing strong vitality is to store them in well ventilated rooms kept dry 
by artiiicial heat. This method of treatment requires that the seeds 
be well cured and well dried before storing. 

(14) If seeds are not well dried A'itality is best preserved at tempera- 
tures just above freezing^ provided that the temperature is maintained 
uniformly. 

(15) In no case must the temperature of the storage liouse be 
increased unless the seed is amply ventilated so that the moisture lib- 
erated from the seed can be carried off readily by the currents of warm 
air. If this precaution is not taken the increased humidity of the air 
confined between the seeds will cause a marked injur}-. For this same 
reason seeds kept at low temperatures during the winter will deterior- 
ate in the warm weather of spring, especially if they contain much 
moisture. 

(16) Most seeds, if first carefully dried, can withstand long expos- 
ures to a temperature of 37° C. (98.6° F.) without injur}^ but long 
exposures to a temperature of from 39° to 40° C. (102.2° to 104° F.) 



SUMMARY. 89 

will cause premature death. If the seeds are kept in a moist atmos- 
phere a temperature of even 30" C. {SQ'^ F.) will soon cause a marked 
injury. 

(17) Seeds can endure any degree of drjdng Avithout injury; that is, 
by drjnng in a vacuum over sulphuric acid. It is believed that such 
a reduction in the water content is necessar}" if vitalit}" is to bo pre- 
served for a long period of years. However, with such treatment the 
seed coats become very firm, and there usually follows a retardation 
in germination as a result of the inability of the seeds to absorb water 
rapidh' enough to bring about the necessary phj-sical and chemical 
transformations for the earlier stages of germination. 

(18) Seeds that are to be sent to countries having moist climates 
should be put up in air-tight packages. Experiments have shown 
that by the judicious use of bottles and paraffined packages seeds can 
be preserved practicalh' as well in one climate as in another. 

(19) It is of the utmost importance that the seeds be drj^ before 
being sealed in bottles or paraffined packages. A drying of ten daJ^s 
at a temperature of from 30" to 35" C. (86° to 95" F.) will usually be 
sufficient. However, a better method to follow is to dry until no 
more moisture is given off at a temperature equivalent to the maxi- 
mum of the region in which the seeds are to be distributed. If this 
is not done, the subsequent increase in temperature will liberate an 
additional quantity of moisture, which being confined in the package 
will, leave the seeds in a humid atmosphere and a rapid deterioration 
in vitality will follow. 

(20) Experiments in storing seeds in open and sealed bottles and in 
packages with definite c^uantities of moisture and at various known 
temperatures have shown a very close relationship between the loss in 
vitality and the increase in water content, the deterioration likewise 
increasing with the temperature. 

(21) Of a series of experiments the average loss in vitality of seeds 
kept in envelopes in a "dr}^ room" w^as 21.19 per cent, "trade condi- 
tions" 30.63 per cent, "basement" -12.28 percent, while the loss in 
the case of seeds stored in bottles was only 8.08, 3.92, and 4.51 per 
cent, respectively. (See Table XXV.) 

(22) Seeds under ordinary conditions of storage respire quite freel}^, 
and respiration is nmch more rapid if much moisture is present. 
Within certain limits respiration is directly proportional to the amount 
of moisture present in the seed and inversely proportional to the 
duration of vitality. 

(23) Respiration is not necessary to the life of seeds, as they can be 
kept in conditions unfavorable for respiratory activity and still retain 
their vitality even better than under normal conditions of storage. 
Even though respiration l)c entirely prevented seeds will continue to 
deteriorate, and sooner or later lose their vitality. 



90 THE VITALITY AND GERMHSTATION OF REEDS. 

(24) The continued deterioration in the vitality of a seed after res- 
piration has ceased indicates a chemical activity within the cells, giving 
rise to a transformation of energy which sooner or later leads to the 
death of the seed, 

(25) Respiration is almost as active in the dark as in the light, pro- 
vided that the temperature and humidity remain the same. 

(26) Ferments and seeds lose all power of activity under similar 
conditions of moisture, and the former are undoubtedh" of the utmost 
importance in metabolic activity, but the evidence at hand goes to 
show that the life of a seed is not dependent on the preservation of 
the particular ferment involved or on the zymogenic substances giving 
rise to the enzyme. 

(27) The life of a seed is undoubtedl}" dependent on many factors, 
but the one important factor governing the longevity of good seed is 
dry7iess. 



LITERATURE CITED. 

Bonnier, G., et Mangin, Louis. La fonetion respiratoire chez les veg6tanx. Ann. 
sc. nat. hot., s^r. 7, 2: 365-380, 1885. 

BoENEMANN, 6. Versuche iiber Erhaltung der Keimfiihigkeit bei importirten Samen 
von Wasserpflanzen wiihrend des Transportes. Gartenflora, 35: 532-534, 1886. 
Also abstract in Bot. Jahresber., Jahrg. XIV, Abt. I, p. 132, 1886. 

Brown, Horace T., and Escombe, F. Note on the inflnence of very low tempera- 
tures on the germinative power of seeds. Proc. Roy. Soc. London, 62: 160-165, 
1897-08. 

■ • On the depletion (A the endosperm of Ilordeum vulgare during germination. 

Proc. Roy. Soc. London, 63: 3-25, 1898. 

• and Morris, M. Germination of some of tlie Clramivav. Jour. Chem. Soc. 



London, 57: 458-528, 1890. 
Dammer, U. Verpackung und Versandt von Samen, welche ihre Keimkraft schnell 

verlieren. Zeitschr. f. trop. Landw., Bd. 1, No. 2, 1897. Abstract in Bot. 

Centralbl., 70: 196-197, 1897. 
De Candolle, Aug. Pvr. Physiologie v^getale (Conservation des graines), v. 2, p. 

618, Paris, 1832. 
De Candolle, C. Sur la vie latente des graines. Arch, des sci. phys. et nat., ser. 4, 

33: 497-512, 1895. Abstract in Amer. Gard., 18: 339, 1897. 

La vie latente des graines. Revue scientifique, ser. 4, 4: 321-326, 1895. 

The latent vitality of seeds. Pop. Sci. Monthly, 51: 106-111, 1897. 

et PiCTET, R. Recherches concernant Faction des basses temfx^ratures sur la 

faculty germinative des graines. Arch, des sci. phys. et nat., s6r. 3, 2: 629-632, 

1879. Abstract in Just's Botan. Jahreslier., Jahrg. VII, Abt. 1, p. 253, 1879. 
Action d'un grand froid prolonge sur des graines. Arch, des sci. phys. et 



nat., ser. 3, 11: 325-327, 1884. Abstract in Just's Bot. Jahresber., Jahrg. XII, 

Abt. 1, p. 26, 1884. 
Detmer, W. Vergleichende Physiologie des Keimungsprocesses der Samen, Jena, 

1880. 
Dewar and McKendrick. On li(inid air. Proc. Roy. Inst., 12: 699, 1892. 
Dixon, 1L H. Vitality of seeds. Nature, 64: 256-257, 1901. 



LITERATURE CITED. 91 

Dixon, H. H. On the germination of seeds after exposure to high temperatures. 

Notes from the Botanical School of Trinity College, Dublin, pp. 176-186, 

August, 1902. 
Edwards et Colin. De I'influence de la temperature sur la germination. Ann. des 

sci. nat. bot., ser. 2, 1: 257-270,1834. 
GiGLioLi, Italio. Sulla resistenza di alcuni semi all' azione prolungata di agenti 

chimici gassosi e liquid. Annuario della R. Scuola Superiore d'Agriccjltura in 

Portici, V. 2, 1880, Napoli, 1881, 51 p. Abstract in Nature, 25: 328, 1882. 

Latent vitality in seeds. Nature, 52: 544-545, 1895. 

Gray, A. Latent vitality of seeds. Ainer. Jour. Sci., 3d ser., 24: 297,.1882. 
GRtJss, J. BeitriigezurPhysiologiederKeimung. Landw. Jahrbiicher, p. 385, 1896. 
Haberlandt, F. Ueber die nntere Grenze der Keiinungstemperature der Samen 

unserer Getreidepflanzen. PHanzenbau I, pp. 109-117, 1875. Abstract in Bot. 

Jahresber., p. 777, 1875. 
Hansteen, B. Ueber die Ursachen der Entleerung der Reservestoffe aus Samen. 

Flora, 79: 419, 1894. 
IsiDORE-PiERRE, J. Uebcr den Einfiuss der Wiirme und des Beizens mit Kalk und 

Kupfervitriol auf die Keimfiihigkeit des Weizens. Ann. Agron., 2: 177-181, 

1876. Abstract in Bot. Jahresber., 4, Abt. 2, p. 880, 1876. 
JoDiN, Victor. Recherches sur la germination. Ann. Agron., 23: 433-471, 1897. 
Sur le resistance des graines aux temperatures eiev^es. Compt. Rend., 129: 

893-894, 1899. 

et Gantier, a. La vie latente des graines. Compt. Rend., 122: 1349-1352, 



1896. 

JisT, L. Ueber die Wirkung hoherer Temperaturen auf die Keimfiihigkeit der 
Samen von Trifolium pratense. Bot. Zeit., 33 Jahrg., p. 52, 1875. 

Ueber die Einwirkung hoherer Temperaturen auf die Erhaltung der Keim- 
fiihigkeit der Samen. Cohn's Beitriige zur Biol, der Pflanzen, 2: 311-348, 1877. 

KocHS, W. Kann die Kontinuitiit der Lebensvorgiiuge zeitweilig voUig unterljrochen 
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Maquenne, L. Sur I'liygrometricite des graines. Compt. Rend., 129: 773-775, 
1899. 

Recherches sur la germination. Ann. agron., 26: 321-332, 1900. 

Contributions ii 1' etude de la vie ralentie chez les graines. Compt. Rend., 

134: 1243-1246, 1902. 

PicTET, R. De I'emploi methodique des basses temperatures en biologie. Arch, sci 
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PiETERS, A. J., and Brown, E. Kentucky Bluegrass seed — harvesting, curing, and 
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Sachs, Julius. Beschiidigung und Todtung durch zu hohe Temperatur. Handbuch 
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92 THE VITALITY AND GERMINATION OF SEEDS. 

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INDEX. 

Page. 

Agriculture, Department, Seed Laboratory, relation to present work 10 

Alabama, Auburn, seed-storing experiment 49 

Allium cepa, selection for experiment 10 

Amyliferous cells, relation to germination of seeds, note 82 

Angaria citrulltis, selection for experiment 10 

Ann Arbor, Mich. , seed-storing experiment 50 

testing experiment 14-22 

Apiacex, Daucus carota, selection for experiment 10 

Apparatus for tests of effect of moisture on vitality of seed 30, 31 

seed testing, description and use 11-12 

Asferacea', Lactuca sativa, selection for experiment 10 

Auburn, Ala. , place for seed-testing experiments 14-22 

Baton Rouge, La., comparison with Ann Arbor and Mobile for seed storing .. 21-22 

seed-storing experiment 49 

testing experiments 14-22 

Bean seed, ice-house storage, effect 28 

selection for experiment 10 

Beans, germination tests, results fur various storage conditions 51, 63-65 

seed, respiration experiment, results 76 

" Valentine," tests _ 83 

Bluegrass, Kentucky, Foa ijralends, heating in curing, effect on seed 43 

Bonnier and Mangin, plant respiration, conclusion 74 

Van Tieghem, tests of respiration of seeds, results 75 

Brassicacex, Brassica oleracea and Raphanus sativus, selection for experiment. . 10 

Brown and Escombe, seed germination experiment 80 

views as to chemical action at liquid-air temperature 79 

Brown and Morris, and Escombe, experiments as to enzymes in germination. 82 

Cabbage, germination tests, results for various storage conditions 53, 63-65 

seed, comparison of storaee in three climates 21-22 

ice-house storage, effect 28 

moisture and temperature tests of vitality 36 

respiration experiment, results 76 

vitality in different packages in varying storage 71-74 

selection for experiment 10 

Carbon dioxid, result of respiration of beans, etc 76, 77, 78 

Carrot seed, germination tests, results for various storage conditions ... ... 55, 63-65 

respiration experiments, results 77 

selection for experiment 10 

Cauliflower seeds, keejiing in moist climate, note 13 

Charcoal, moss, etc. , shipping seed in packing 47 

Chemical activity, relation to latent life 80 

Clement, suggestion for storage of seed 45 

Climates, different, causes of loss of vitality in .seeds, discussion 22-24 

Climatic conditions, effect on vitality of seeds, discussion 13-22 

Corn, sweet, germination tests, results for various storage conditions. . . 56-57, 63-65 

selection for experiment 10 

Coville, Frederick V. , preface on purpose and scope of present study 5 

Cucvrbitacex, Anguria citrullus, selection for experiment 10 

Curing and (trying of seeds, necessity for thoroughness 45 

of seed, importance 87 

De Candolle, Aug. Pyr., remarks on conservation of seeds 44 

suggestion regarding vitality of seeds 75 

C. , views on respiration of seeds 78 

Diastase, use in experiments on vitality of seeds 85 

Dry atmosphere in open bottles, effect on vitality of seeds 34 

sealed bottles, effect on vitality of seed 34 

heat, effect on vitality of seed, note -- 31 

Drying and curing of seeds, necessity of thoroughness 45 

93 



94 INDEX. 

Page. 

Dryness, most iiiiiiortant factor in prolonged vitality of seud 90 

relation to preservation of vitality of seed 87, 88, 89, 90 

Endosperm of grasses, relation to germination, notes 82 

Enzymes in seeds, part in preserving vitality 82-87 

Escombe and Brown, experiments as to enzymes in germination 82 

seed -germination experiment 80 

views as to chemical action at liquid-air temperature ... 79 

Fabacew, Pisit7n satinmi and Phaseolus vulgaris, selection for experiment 10 

Fazy-Pasteur, suggestion for storage of seed 45 

Ferments, relation to vitality of seeds 90 

unorganized, relation to vitality of seeds 82-87 

Ferry Botanical Fellowship, seed study, relation to present work 10 

Ferry, D. M. , & Co. , seed for exi:»eriments 10, 15 

Florida, Lake City, seed-storing experiment 49 

testing experiment 14-22 

Gardener, market, value of good seed 46-47 

Gardeners, complaints of seeds, note 13 

"Geneva tester" for germination of seeds, moditications and use 11-12 

Germination and vitality of seeds, conclusion from present study 87-90 

of seeds at low temj^eratures 26-27 

in ice house, effect of package 27, 28 

various seeds, percentage under differing storage 63-65 

part of enzymes 82 

tests and apparatus, discussion 11-13 

results '. 50-65 

Germinator, seed testing, metliod of use 12 

Giglioli, conclusion as to chemical activity in latent life 80 

experiments with seed of Medicago sativa 79 

remarks on vitality of seeds 45 

Grasses, endosperm, relation to germination 82 

Gray, contention as to suffocation of seeds 79 

Griiss, citation as to grass endosperm 82 

Gulf of Mexico, effect of moisture on seeds 13 

Hansteen, citation as to grass endosperm 82 

Harvesting, relation to vitality of seeds 87 

Heating, excessive, danger in curing seed 87 

Hygroscope, crude, imj^rovisation from awns in seed testing 31 

Hydrolysis, presence in experiments on enzymes in seeds, notes 83, 84, 85, 86 

Ice, packing of seeds, effect on vitality, remarks 26-29 

Incubator, seed, test for effect of moisture on vitality 29 

Indian Territory, Wagoner, place for seed-testing experiments 14-22 

seed-storing experiment 50 

Jodin, seed-germination experiment, note 80 

statement as to respiration of seeds 75 

Keeping seeds, discussion {see also Storage) 65-74 

Kochs, seed-resjiiration experiment 79 

Lacluca sativa, selection for experiment 10 

Latent life, relation of chemical activity 80 

Lettuce, comparison of storage in three climates 21-22 

germination tests, results for various storage conditions 58, 63-65 

seed, ice-house storage, effect 28 

loss of vitality in tropical climate, note 25 

moisture and temperature test of vitality 36 

respiration experiment, results 77 

selection for experiment 10 

Liliacere, Allium cepa, selection for experiment 10 

Longevity of seed, dryness most imjiortant factor 90 

Lycoj)ersicon lycopersicum, selection for experiment 10 

Maquenne, statement as to seeds in low temperatures, note 81 

suggestion as to respiration of seeds 74 

suggestions as to vitality of seeds 83 



INDEX. 95 

Page. 

Market gardener, value of good seed, remarks 46-47 

Maturity, relation to vitality of seeds 87 

Mangin and Bonnier, plant respiration, conclusion 74 

Medicago saliva, seed, experiments of Giglioli 79 

Giglioli and Samek 80 

Michigan, Ann Arbor, seed-storing experiments 50 

University, seed study, relation to present work 10 

Mobile, Ala., comparison with Baton Rouge and Ann Arbor for storing seed.. 21-22 

place for seed-testing experiments l^t-22 

seed-storing experiment 49 

Moist atmosphere in sealed bottles, severe injury to seeds 33 

Moisture and temperature, effect upon vitality of seeds, discussion 24-36 

summary of results . . 35 

relation to vitality of seed, tables and comment. . . 38-44 

effect on vitality of seeds at high temperatures, remarks 29 

in iixed temperatures, discussion 36-44 

hindrance in keeping seeds, provision 13 

relation to endurance of heat by seed 25 

longevity of see<l 1 87, 88, 89, 90 

tqgt of seeds in special packages 66 

Morris and Brown, experiments as to enzymes in germination 82 

Moss, charcoal, etc. , shipping seed 47 

New Hampshire, Durham, place for seed-testing experiments 14-22 

seed-storing experiment 50 

New Orleans, rapidity of deterioration of seed 47 

Newcombe, Dr. F. C. , direction of present study 10 

Nobbe, seed germination experiment, note 80 

Oily seed, resistance of low temperatures, note 28 

Onion, germination tests, results for various storage conditions 59, 63-65 

seed, comjiarison of storage in three climates 21-22 

ice-house storage, effect 28 

moisture and temperature test of vitality 36 

respiration experiments, results 77-78 

vitality in different packages in varying storage 71-74 

selection for experiment 10 

Packages, seed, different kinds for moisture test 66 

relation to preservation of vitality of seeds 89 

special, experiments in shipping and keeping seeds 65-74 

Packing seed for shipping experiments 47 

Pansy, germination tests, results for various storage conditions 60, 63-65 

selection for experiment 10 

Paraffined packages, vitality of seeds in storage 69-71 

Pea, selection for experiment 10 

Peas, germination at temperature of ice water, remarks 27 

tests, results for various storage conditions 52, 63-65 

seed, moisture and temperature, test of vitality 36 

Phascolus vulgaris, selection for study 10 

Phlox, germination tests, results for various storage conditions 60, 63-65 

Pisum sativum, selection for experiment 10 

Planters, complaints of seeds, note 13 

Poa pralensis, heating in curing, effect on seed 43 

Poarex, Zea mays, selection for experiment, note 10 

Poison, danger from brass and copper in seed testing, notes ■ 11, 12 

Polemoniacese, Phlox drummondii, selection for study 10 

Porto Rico, San Juan, seed storing experiment 48 

testing exjieriments 14-22 

Precipitation and temperature, relation to vitality of seeds, percentages 23 

effect on vitality of seeds, graphic reiaresentation 24 

Protoplasm, changes in respiration of seed 78 

Protoplasts, changes in respiration experiments 79 

Puriewitsch, citation as to grass endosperm 82 

Radish, germination tests, results for various storage conditions 54, 63-65 

selection for experiment 10 

Respiration, necessity to life of seeds, remarks 79 

of seeds, discussion 74-82 



9(3 INDEX. 

Page. 

Respiration ui seed?, summary of conclusions 81-82 

relation to vitality of seeds 89, 90 

Romanes, seed respiration experiment 79 

Samek, seed germination experiment, note 80 

Sliarpe, citation as to enzymes 83 

Shipping and keeping of seeds in special packages, discussion 65-74 

storing seeds, method for preservation of vitality 44-65 

seed in charcoal, moss, etc. , remarks 47 

Soaking seeds for germination tests, advantage 12 

Solanacew, Lycopersicon lycopersicmn, selection for experiment 10 

Spalding, Prof. V. M. , direction of present study 10 

Starch in seed, relation to germination in ice-house storage 28 

Storage (keeping) and shipping of seeds in special packages, discussion 65-74 

room, warehouse, character for seeds, remarks 46 

seed, relation to preservation of vitality 88, 89 

Storing and shipping seeds, methods for preservation of vitality 44-65 

seeds, relative merits of Mobile, Baton Rouge, and Ann Arbor 21-22 

Temperature and moisture, effect on vitality of seed, discussion .^ 24-36 

summary of results 35 

relation to vitality of seed, tables and comment. . . 38-44 

precipitation, relation to vitality of seed, percentages 23 

maximum limit of endurance by seed, variation 25 

relation to vitality of seeds 87, 88, 89-90 

Temperatures, fixed, effect of (lefinite moisture on vitality of seed, discussion. . 36-44 

high, vitality of seeds, effect of moisture 29 

Test, germination, first, for climate, results, tal)le and conunent 15-16, 18-21 

second, for climate, results, table and comment 16-17, 18-21 

Tester, Geneva, germination of seeds, modification and use 11-12 

Testing seeds, conditions of experiments 14, 29-31, 36 

Tests, germination, results 50-65 

various vegetable seeds 11 

seed, for effect of moisture on vitality at high temperatures 29 

vitality, importance of nearness to planting time 47 

Tliompson, citation as to enzymes 83 

Tomato, germination tests, results for various storage conditions 61, 63-65 

seed, ice-house storage, effect 28 

moisture and temperature test of vitality 36 

selection for experiment 10 

Tropical climate, loss of vitality of lettuce seed 25 

Vacuum, seed respiration experiments 79 

Van Tieghem and Bonnier, tests of respiration of seeds, results 75 

Molarea', ]'iola tricolor, selection for experiment 10 

Vitality and germination of seeds, conclusions from present stuily, suunnur\-. . 87-90 

cabbage and onion seed, relation to storage and package 71-74 

seed, effect of c:limatic conditions, discussion 13-22 

definite moisture in fixed temperatures, discussion 36-44 

temperature and moisture, discussion 24-36 

enzymes in preservation 82-87 

loss for various seeds under different storage conditions 63-65 

in different climates, causes 22-24 

with varying moisture at ordinary temperature 85 

low, worse tlian dead seed, note 46 

preservation l>y methods of storing and ship[)ing 44-65 

relation of moisture and temperature, tal)les and conunent 38-44 

storage in different kinds of packages, results 68 

Warehotise, seed, storage, character, remarks 46 

AVater content of seeds, increase, effect on vitality 44 

Watermelon, gemination tests, results for various storage conditions 62, 63-65 

seed, ice-house stoi-age, effect 28 

selection for experiment 10 

Waugh, citation as to enzymes 83 

Zea mays, selection for experiment, note 10 

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